any possibilities that the MySQL UPDATE the table with wrong data
...only if you give it the wrong data. You need to do some serious testing and code reviewing. If what you're saying is genuinely not the result of a human problem (which is still quite likely) then you have a very fundamental and serious bug, if the code is capable of recording the wrong user as having added a record (especially as it seems to be doing so inconsistently, from what you say). I'd still say though that there's just as good a chance, if not more chance, that this is actually human error or human malice.... —
ADyson 1 min ago