Recurring Problems
If something happens once, it’s an exception, an accident, and you shouldn’t worry about it too much.
If it happens twice, it’s difficult to say that it’s a recurring pattern, but it will likely happen again.
And if it repeats more than twice, it’s certainly something that will keep recurring until you deal with it. But more importantly, it’s a sign of a deeper systemic problem that you should address as soon as possible.