So, in essence, guess for mistakes that could cause those issues ?
Understood that that was the intention. This time you (or rather we) got lucky that the first suggestion was the right one (as we’ve encountered this before), but if we have to start listing everything someone could’ve done wrong in his code that could lead to issues, that would take many times longer than if we were able to take a look at it quickly.
In general, if you suspect issues with your code, please post that code. In the same sense that “a picture says more than a thousand words”, it is also true that “you actual code says more than a thousand vague descriptions of said code and its issues”. When it comes to debugging issues we can’t see, there’s no such thing as too much information.