Overly specific interpretation of terms

Imagine the following conversation:

A: Please don't change the rules every four weeks!
B: We don't change the rules every four weeks!
A: You changed it twice in the last two months, how do you call that?
B: But one of those was after 3 weeks and the other after 5 - so see, not every four weeks!

Or in a similar tone:

A: Do you admit that nobody ever looks at the feedback you receive (via the feedback form)?
B: That's not true, we look at the feedback.
A: But I can see that feedback I've submitted weeks ago has not been acted on.
B: We don't act on the feedback, but we have someone who looks at it.

This may sound like a parody but actually paraphrases some discussions I had with a certain colleague.

I'm not sure if that actually qualifies as a fallacy or if it is just an unfair rhetoric tactic - but there are some aspects of "nit-picking" here and it's definitely some attempt to derail a discussion, i.e. a "red hering" of some sorts.

Any other ideas how to classify this?