Deleting version and swapping to another version does not update custom fields

When I delete a project version, it prompts me to swap the "Affects Version/s" or "Fix Version/s" field values to another valid version. It does this correctly, however I would expect that any custom fields which are "version" type would also be changed from the deleted version to the new version I have chosen. It seems they are not changed, so the custom field values show up as blank after the version is deleted.

As a workaround, I guess I can run a SQL query to change the customfieldvalue for all issues in the project.

Thanks,
Bill