There's a bug where the frame gen isn't working when you load in. you have to turn it off and turn back on. Also delete your GL/GX cache and rolling cache on msfs 2024. buttery smooth on SU3.
I've witnessed it happening via Volanta in 2020 as well. it usually happens when the weather bugs out. I love what they've done with the plane, I just hope there's a fix for that because of right now it's a hit or miss for long haul routes.
I had the same issue flying through Romania, I have AP protection on and active sky FS on. the autopilot didn't disconnect, the plane went into heading mode by itself luckily it was on the same trajectory as the airport.