When adding new phone record for a contact and it's the ONLY phone record, getting ERROR

This is linked to this bug: http://issues.civicrm.org/jira/browse/CRM-5051

If you enter ONE phone number in a contact record for someone who doesn't already have a phone number and click "Save", you get an error saying that you have to mark one phone as primary.

This happens even though the person only has one phone number and there is no "primary" radio button because there aren't two phones. The workaround is to click "add phone number" which makes the radio button show up, clicking the "primary" for the original number, and not entering anything into the second phone number field.

I think this is also true for email, etc., as reported in the linked bug: http://issues.civicrm.org/jira/browse/CRM-5051

It says it's been verified for 3.1 but we're using 3.1.3 and this error is still occurring. I can't recreate it in sandbox.civicrm.org.