This log file (attached, here) represents a database diagnostic test, which produced a Metabase Warning. Despite this, the conclusion of the test states that the diagnosis completed successfully, despite that one warning. A subsequent test, immediately after this 1st one, says that there are no errors. Does this log file say anything about that Metabase error?
This is normal. Nothing to worry about.
You did not attach the diagnosis log file, though.
What I attached was the log file that I ordinarily would attach, after a questionable event, with IMatch set to Debug Logging. Is this file a different one than the file that is produced, with IMatch performing a Database Diagnostics?
The database diagnosis uses its own log file. You can open it directly from database diagnosis dialog after the diagnosis has completed. Just click on the "View LogFile" button at the bottom.
See The Log File (https://www.photools.com/help/imatch/#rmh_dlg_dbdiag.htm?dl=h-4)