Can’t Delete DTH from IDE although no devices using it


I have a custom Zigbee DTH based on a Smart Things DTH which I created ages ago. I’m trying to delete because it has a fingerprint I can no longer comment out and thus picks up a device which I’m trying to pair to an Edge driver.

I have confirmed that there are no devices using it. The message I get is

could not delete: [physicalgraph.device.JoinFingerprint#4115465]; SQL [delete from join_fingerprint where id=? and version=?]; constraint [null]; nested exception is org.hibernate.exception.ConstraintViolationException: could not delete: [physicalgraph.device.JoinFingerprint#4115465]

I have rebooted hub, reverified that there is no device using this DTH (which would give me a different message anyhow).

(Also, I have deleted multiple other DTHs with no problem today).