I have no idea if this will fix the issue that others are experiencing, however this is something I always do after any update. The information below is for the MS Store version of MSFS. I am not sure how it works for steam.
There is a repository of scenery that MSFS uses, both in the OFFICIAL and the COMMUNITY folder under the name Content.xml located in C:\Users\ YOUR USER NAME \AppData\Local\Packages\Microsoft.FlightSimulator_8wekyb3d8bbwe\LocalCache
It is a file that can be viewed using a text editor.
I always empty the community folder before any updates.
After I update I restart the PC
I then browse to this file location and delete Content.xml
I then run MSFS and it rebuilds this file
I then exit MSFS
I move all the community folder contents back into the Community folder and re run MSFS
It then updates the Content.xml file with all the community folder scenery.
TL;DR deleting Content.xml and running MSFS with an empty community folder, exiting the sim and readding contents to the community folder and then rerunning MSFS may correct this issue. It might be worth a try?
Update: These steps don’t correct the issue