Bucking at running temp

What is your question?

I have a 2010 Nissan Rogue. Once the car is well warmed up, and driven 30 or so mins, the rpms will randomly bounce. Its a very light "bucking" that can be felt in the car, and noticable on the rpm gauge. It's very random and mostly happens when accelerating between 150k-200k rpms. Otherwise runs and idles fine.

What makes this problem better or worse?

N/A

How long has your 2010 Nissan Rogue had this problem?

A week or so