I just started having the issue too. It’s not always present, and I have no idea how or why it comes and goes…
Enabling Fast Synch in the Nvidea control panel has completely resolved it for me. There are some good posts explaining what causes screen tearing in one of the other threads on the forum.
I am going to close this thread and refer anyone who still has this issue to vote/ provide feedback in this earlier thread, which appears to be reporting the same isse:
https://forums.flightsimulator.com/t/glitchy-pixels-at-top-of-screen/430295/