Contact import silently aborts if related organisation Yes or No field has value Yes

To replicate:
(1) Create a custom field of type "Yes or No", called e.g. "Are you sure".
(2) Import Contacts Step 1: choose data source SQL query, enter:
SELECT 'Testy' AS `First Name`, 'Tester' AS `Last Name`,'Test Org' AS `Organization Name`, 'testorg@civicrm.org' AS email, 'Yes' AS sure;
and leave import options as default (Ind., skip, no saved field mapping).
(3) Import Step 2: accept the correct defaults offered for First/Last Name; for Org Name, Email & sure, choose "Employee of" and select Org Name, Email & "Are you sure" fields from Organization.
(4) At import step 3, choose Add to new group TestImport & proceed with import.

• Summary at Step 4 shows 1 contact imported. Only the Individual is imported, not the related Org. Group TestImport is not created (or if you chose an existing group, no contact is added to it). No error message.

Repeating the above with value 1 instead of 'Yes' for the Yes or No field works correctly.

CIvi 2.2.8, Drupal 6.12, PHP 5.2.10, MySQL 5.0.45