I noticed that too and a lot of times I have disks that where suprise removed (reported by the windows Event Viewer) recently. btw. I don`t have a physical drive 4 and this is not an USB flash Drive etc.
my only games that I bought at the WIndows Store are Minecraft and Flight Simulator 2020.
You can even find in the device manager at “disk drives” sometimes those Virtual Drives that are created XVD (Xbox Virtual Disk).
If you can`t see them, click on view-> show hidden devices
There is also a new Gaming Service app, Microsoft.GamingServices app, that installs two drivers; xvdd.sys = XVD Disk Driver (Microsoft Gaming Filesystem Driver) gameflt.sys = Gaming Filter (Microsoft Gaming Install Filter Driver).
I`ll already tried to delete this gaming service app and i was successful doing so, but Flight SImulator will ask you to install it again when starting or you cant play.