Mistakenly Making Flaw Questions into Weaken Questions

7SageThanks

Does anyone else find themselves mistakenly solving flaw questions as weaken questions when considering certain answer choices?
What I will find myself doing when evaluating certain answer choices is saying to myself, "Well if this were true, it wouldn't necessary weaken the argument, so it isn't the flaw of the argument"
I think this is incorrect because the best method for answering those two question types are different, but I don't actually know on a deeper level why the two methods don't sometimes overlap. Or maybe they do and I'm not always wrong in doing that.
Instead, I just accept that that is the wrong way to go about answering the question and try to catch myself when I do it and revert back to the correct method to answering a flaw question.

I know this is a bit abstract, but if someone could help explain more clearly why those two methods don't overlap sometimes when considering certain answer choices that would be helpful.