Hi, Sarah.
Thanks for letting us know about this issue.
Certification completion history is different from the current certification completion record. In order to delete the current completion record, the users would need to be unassigned from the certification first or the record updated using the completion editor.
Unfortunately, there is no way to correct the completion records in bulk, which I appreciate will be a frustrating and laborious process.
The only way to delete completions in bulk would be deleting the certification, which would delete all related current completions and historical completions for the certification. Deleting the certification is risky because if you have imported historical completions and users have completed the certification and on different paths, etc., it could be complicated to recreate it and try to map everything correctly again and it would also affect messaging.
A better option might be to restore the previous certification state from a database backup.
We would recommend getting in touch with your Totara Solutions Partner and make them aware of the issue (if you have not already) because they will be in a position to provide support, gather more details from you and get in touch with Totara Support if further guidance is needed.
If you have not contacted your Totara Solutions Partner, we recommend providing your Totara Learn site version e.g. 12.18 and as much detail as possible, for example, how the problem occurred, when it happened, the certification and users affected.
I hope this helps clarify the current options and provides you with a way to move forward.
Thanks.
Tom Ireland, Totara Support