I only purchased navigraph the other day for use in MSFS, After installing it using the latest version I noticed that whatever aircraft I use the sim has started to stutter, almost pause for a good second every 15s-45s ish.
After removing the navigraph folder from the Microsoft Flight Sim 2020\Community folder and reloading the sim everything works fine. And after uninstalling and re-installing loads of different things I have certainly narrowed it down to navigraph. (it also started after I purchased it too)
Just fyi I think I have found a solution of sorts. I found that if I ran the msfs executable as an administrator then it no longer had the issue, When I ran it from the normal steam desktop icon it was a stuttery mess again.
At least I can run it as admin for now… Only tested quickly on a cessna and I will do more testing and report back if I run into any more issues