I got this error when trying to "undo logged change". It happened for both the standard series column and a custom taglike column.
Code:
calibre, version 5.13.0
ERROR: AL: Undo : Sorry, AL cannot Reverse/Undo the selected line. <br><br><b>Unsupported table_action: insert
Thank you.
EDIT: Also, just out of curiosity, is the log itself stored the _audit_log table in metatdata.db, or is that used for something else?