Hello.
Firebird 3.0.10 64 bit, Red Hat Enterprise Linux 8.9 (Ootpa).
Following entry appeared in firebird.log. According to the request I'm contacting you :-)
Database: xxxxx
internal Firebird consistency check (record disappeared (186), file: vio.cpp line: 3939)
Attempt to change state of the already committed transaction.
Please, notify Firebird developers.
Best regards,
Tomasz.