Activity Report fatal error when including custom field set with long name

Following the update to 4.7, I discovered that one of the custom field sets we use for Activities causes the Activity report to fail with the error message 'DB Error: no such field' when you try to include any of its fields as a column or a filter.

I initially assumed it was just related to that field set, as other field sets for Activities didn't result in an error, but going through the problem again, I was able to replicate it with a new custom field set on both my installation and the 4.7.2 demo (although there it just says it's an unknown error). It appears that any custom field set name over 27 characters results in this error.

From my error log:

Feb 12 11:07:08 [info] $Fatal Error Details = Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => -19
[message] => DB Error: no such field
[mode] => 16
[debug_info] => CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COLLATE utf8_unicode_ci AS
SELECT civicrm_contact_target.sort_name as civicrm_contact_contact_target, civicrm_contact_target.id as civicrm_contact_contact_target_id, activity_civireport.id as civicrm_activity_id, activity_civireport.source_record_id as civicrm_activity_source_record_id, activity_civireport.activity_type_id as civicrm_activity_activity_type_id, activity_civireport.subject as civicrm_activity_activity_subject, activity_civireport.activity_date_time as civicrm_activity_activity_date_time, activity_civireport.status_id as civicrm_activity_status_id, address_civireport.country_id as civicrm_address_country_id, value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179 as civicrm_value_gwl_hears_me_equal_opps_form_33_custom_179, address_civireport.street_name as civicrm_address_street_name, address_civireport.street_number as civicrm_address_street_number, address_civireport.street_address as civicrm_address_street_address, address_civireport.city as civicrm_address_city, address_civireport.postal_code as civicrm_address_postal_code
FROM civicrm_activity activity_civireport
INNER JOIN civicrm_activity_contact activity_contact_civireport
ON activity_civireport.id = activity_contact_civireport.activity_id AND
activity_contact_civireport.record_type_id = 3
INNER JOIN civicrm_contact civicrm_contact_target
ON activity_contact_civireport.contact_id = civicrm_contact_target.id

LEFT JOIN civicrm_address address_civireport
ON (civicrm_contact_target.id =
address_civireport.contact_id) AND
address_civireport.is_primary = 1
WHERE activity_civireport.is_test = 0 AND
activity_civireport.is_deleted = 0 AND
activity_civireport.is_current_revision = 1 AND ( activity_civireport.activity_type_id IN (23) ) [nativecode=1054 ** Unknown column 'value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179' in 'field list']
[type] => DB_Error
[user_info] => CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COLLATE utf8_unicode_ci AS
SELECT civicrm_contact_target.sort_name as civicrm_contact_contact_target, civicrm_contact_target.id as civicrm_contact_contact_target_id, activity_civireport.id as civicrm_activity_id, activity_civireport.source_record_id as civicrm_activity_source_record_id, activity_civireport.activity_type_id as civicrm_activity_activity_type_id, activity_civireport.subject as civicrm_activity_activity_subject, activity_civireport.activity_date_time as civicrm_activity_activity_date_time, activity_civireport.status_id as civicrm_activity_status_id, address_civireport.country_id as civicrm_address_country_id, value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179 as civicrm_value_gwl_hears_me_equal_opps_form_33_custom_179, address_civireport.street_name as civicrm_address_street_name, address_civireport.street_number as civicrm_address_street_number, address_civireport.street_address as civicrm_address_street_address, address_civireport.city as civicrm_address_city, address_civireport.postal_code as civicrm_address_postal_code
FROM civicrm_activity activity_civireport
INNER JOIN civicrm_activity_contact activity_contact_civireport
ON activity_civireport.id = activity_contact_civireport.activity_id AND
activity_contact_civireport.record_type_id = 3
INNER JOIN civicrm_contact civicrm_contact_target
ON activity_contact_civireport.contact_id = civicrm_contact_target.id

LEFT JOIN civicrm_address address_civireport
ON (civicrm_contact_target.id =
address_civireport.contact_id) AND
address_civireport.is_primary = 1
WHERE activity_civireport.is_test = 0 AND
activity_civireport.is_deleted = 0 AND
activity_civireport.is_current_revision = 1 AND ( activity_civireport.activity_type_id IN (23) ) [nativecode=1054 ** Unknown column 'value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179' in 'field list']
[to_string] => [db_error: message="DB Error: no such field" code=-19 mode=callback callback=CRM_Core_Error::handle prefix="" info="CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COLLATE utf8_unicode_ci AS
SELECT civicrm_contact_target.sort_name as civicrm_contact_contact_target, civicrm_contact_target.id as civicrm_contact_contact_target_id, activity_civireport.id as civicrm_activity_id, activity_civireport.source_record_id as civicrm_activity_source_record_id, activity_civireport.activity_type_id as civicrm_activity_activity_type_id, activity_civireport.subject as civicrm_activity_activity_subject, activity_civireport.activity_date_time as civicrm_activity_activity_date_time, activity_civireport.status_id as civicrm_activity_status_id, address_civireport.country_id as civicrm_address_country_id, value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179 as civicrm_value_gwl_hears_me_equal_opps_form_33_custom_179, address_civireport.street_name as civicrm_address_street_name, address_civireport.street_number as civicrm_address_street_number, address_civireport.street_address as civicrm_address_street_address, address_civireport.city as civicrm_address_city, address_civireport.postal_code as civicrm_address_postal_code
FROM civicrm_activity activity_civireport
INNER JOIN civicrm_activity_contact activity_contact_civireport
ON activity_civireport.id = activity_contact_civireport.activity_id AND
activity_contact_civireport.record_type_id = 3
INNER JOIN civicrm_contact civicrm_contact_target
ON activity_contact_civireport.contact_id = civicrm_contact_target.id

LEFT JOIN civicrm_address address_civireport
ON (civicrm_contact_target.id =
address_civireport.contact_id) AND
address_civireport.is_primary = 1
WHERE activity_civireport.is_test = 0 AND
activity_civireport.is_deleted = 0 AND
activity_civireport.is_current_revision = 1 AND ( activity_civireport.activity_type_id IN (23) ) [nativecode=1054 ** Unknown column 'value_gwl_hears_me_equal_opps_form_33_civireport.what_is_your_postcode__179' in 'field list']"]
)

Feb 12 11:07:08 [info] $backTrace = #0 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Error.php(235): CRM_Core_Error::backtrace("backTrace", TRUE)
#1 [internal function](): CRM_Core_Error::handle(Object(DB_Error))
#2 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\PEAR.php(931): call_user_func((Array:2), Object(DB_Error))
#3 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB.php(976): PEAR_Error->PEAR_Error("DB Error: no such field", -19, 16, (Array:2), "CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#4 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\PEAR.php(564): DB_Error->DB_Error(-19, 16, (Array:2), "CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#5 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\common.php(1905): PEAR->raiseError(NULL, -19, NULL, NULL, "CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...", "DB_Error", TRUE)
#6 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\mysql.php(895): DB_common->raiseError(-19, NULL, NULL, NULL, "1054 ** Unknown column 'value_gwl_hears_me_equal_opps_form_33_civireport.what...")
#7 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\mysql.php(328): DB_mysql->mysqlRaiseError()
#8 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\common.php(1216): DB_mysql->simpleQuery("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#9 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\DataObject.php(2435): DB_common->query("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#10 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\DB\DataObject.php(1627): DB_DataObject->_query("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#11 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\DAO.php(334): DB_DataObject->query("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#12 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\DAO.php(1209): CRM_Core_DAO->query("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...", TRUE)
#13 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Report\Form\Activity.php(775): CRM_Core_DAO::executeQuery("CREATE TEMPORARY TABLE civireport_activity_temp_target CHARACTER SET utf8 COL...")
#14 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Form.php(423): CRM_Report_Form_Activity->postProcess()
#15 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\QuickForm\Action\Submit.php(74): CRM_Core_Form->mainProcess()
#16 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\HTML\QuickForm\Controller.php(203): CRM_Core_QuickForm_Action_Submit->perform(Object(CRM_Report_Form_Activity), "submit")
#17 C:\xampper\htdocs\able\sites\all\modules\civicrm\packages\HTML\QuickForm\Page.php(103): HTML_QuickForm_Controller->handle(Object(CRM_Report_Form_Activity), "submit")
#18 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Controller.php(351): HTML_QuickForm_Page->handle("submit")
#19 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Utils\Wrapper.php(113): CRM_Core_Controller->run()
#20 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Report\Page\Report.php(72): CRM_Utils_Wrapper->run("CRM_Report_Form_Activity", NULL, NULL)
#21 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Invoke.php(312): CRM_Report_Page_Report->run((Array:3), NULL)
#22 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Invoke.php(86): CRM_Core_Invoke::runItem((Array:14))
#23 C:\xampper\htdocs\able\sites\all\modules\civicrm\CRM\Core\Invoke.php(54): CRM_Core_Invoke::_invoke((Array:3))
#24 C:\xampper\htdocs\able\sites\all\modules\civicrm\drupal\civicrm.module(454): CRM_Core_Invoke::invoke((Array:3))
#25 [internal function](): civicrm_invoke("report", "activity")
#26 C:\xampper\htdocs\able\includes\menu.inc(527): call_user_func_array("civicrm_invoke", (Array:2))
#27 C:\xampper\htdocs\able\index.php(21): menu_execute_active_handler()
#28