After upgrade from 14.2 to 15.2, all custom fields in the benefit plans are blank. The data in them is gone
This problem occurs during an upgrade from 14.2 to 14.3. Even if a customer has chosen to upgrade to a higher version, the upgrade from 14.2 to 14.3 is still happening behind the scenes.
This occurs during the upgrade from 14.2 to 14.3 because the structure of the tables for the benefit plans changed and the attributes are automatically upgraded to allow this change. This problem was submitted as a defect to development: DE36923
The official recommendation is to xog the Benefit plan data (including custom fields) out before the upgrade and back in after the upgrade.
DE36923 was marked as Will Not Fix because that version of PPM is no longer being patched.