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phiro - my suggestion is you (and everyone else) should run the Check Library option periodically (e.g. weekly, monthly, quarterly, whatever). Check Library is also an option for the calibredb command, it outputs to a CSV.
I do it as part if my 'weekly housekeeping'. If it reports anything, then while I'm fixing the problem I'll probably recall how I created the problem, which acts as a timely reminder to 'stop doing that'
BR