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Solved via editing the Guest machine's group policy to NOT use the WDDM RDP display driver for RDP sessions, instead using the XDDM driver.

As it might be fixed by a Windows update (which my WSUS people might have not approved yet) I'm not rolling out the Policy change to my whole organization at this time. Hopefully this information helps you!

We are also having this issue. Everything is fine on the console session, but when Control switches to one of the guest's RDP session, the mouse is almost unusable.

This is a pretty high priority for us over here as well. As much as we love Control, if we can't get proper 2FA going without modifying the Description field, I think we might need to not renew. :\

Similar issue over here. If different wallpapers are set per screen, the wallpaper that was on screen 1 is restored to all screens upon disconnect.

I made an account just to suggest this same thing!