I think it has something to do with scenery loading in. I also get weird 2-3 second big freezes. Except for me it happens one time, and that’s during descent. However, ive noticed that it happens again during descent and approach if I have a 3rd party airport installed. I think it’s the sim trying to load the airport in. I get a 1 second freeze though. Other than that 99% of a flight, I have no issues.