If you mean about people: I never overthink them. I always understate and underappreciate the problem. Then I'm faced with an angry horde of ES's who hate me. I don't know what I do, now explain what I do wrong so that we can work through this!
I'm not sure what "making them into problems" means, but when I overthink that tends to lead to delayed action or no action at all. So the thinking itself isn't the problem, it's the inactivity that results from it that can cause major problems.
Do you sometimes over think certain things, and unintentionally make them into much larger problems because of your overthinking?
If by "overthink" you mean getting myself into trouble ruminating on a problem, yes. I might originally believe the problem important but can't evaluate its importance properly. This might occur if the reward of a solution were great while failure was expected. It's the pursuit of a goal. What happens is fail fail fail and this might end up being a waste of time. It's an evaluation problem itself. INTPs often find proper evaluation difficult, but so can anyone who pursues a goal with intensity and obstinacy. It doesn't take just thinking for this to happen.