This has been a long standing issue with Nautilus' Desktop Icon view. It'll only be fixed by us replacing it wholesale, like what upstream GNOME did by moving it out of Nautilus and into a GNOME Shell extension in newer stack upgrades (we hold Nautilus back currently to keep the functionality).
It's not a priority over people having desktop icons in the first place, but having an improved desktop icon view is something I do want to provide people (alongside a new Nautilus), so that's something I'm going to be working to address for either Budgie 10.5.2 (not Budgie 10.5.1) or further down the road with Budgie 11.
