Given circumstances already stated, not knowing that file in _original from a decrypt process has to be deleted before a separate crop process is run isn't reasonably characterised as "meddling fingers", and to call running a separate crop process as an "edge case" is also unrepresentative. Please, moderate your tone.No, what happened is the backup copy of the original uncropped file failed to be created as expected, so the process took the least risky option and aborted. Under normal circumstances this wouldn't happen, but the invisibility of error messages definitely doesn't help.
Not standard, but the result of meddling fingers while you were exploring. An edge case.
No need, it will happen any time you try to re-run a crop without tidying up from the previous run properly.