I can reproduce this with at at least one more application (Zoiper 5 Desktop).
If I hover over the "ghost" area I get mouse pointer hints for both, Anydesk and Zoiper on different parts of the area.
If I disable the "legacy tray icons" option in the extension and log out of Gnome session and log in again, the ghost-area is gone.
To me, this looks like a problem in the handling of the legacy tray icons.
This is not a bug in Anydesk.
I can reproduce this with at at least one more application (Zoiper 5 Desktop).
If I hover over the "ghost" area I get mouse pointer hints for both, Anydesk and Zoiper on different parts of the area.
If I disable the "legacy tray icons" option in the extension and log out of Gnome session and log in again, the ghost-area is gone.
To me, this looks like a problem in the handling of the legacy tray icons.