Since upgrading to 12.3.1 I've gained a couple of Phantom folder on the desktop. They can be moved but clicking on them does nothing:
Are you sure those folders are connected to Opus in some way?
They were not there prior to loading the new beta and were there straight after the install reboot.
Strangely enough right clicking allowed me to delete them (when selecting and hitting delete didn't). So resolved anyway.
A lot of things can happen when you reboot, including updates to other software that were pending.
Maybe, no way of telling as they could not be opened to anything.
What do you see when you open the "desktop"-folder in Explorer (the one within your user-account and also the one within "all users")?
Nothing unusual, but then again the phantoms have been deleted - they do not appear in the Recycle Bin.
If you have ghost folders/files, you can try to delete them using command line with admin rights. I remember having an unnamed ghost folder few years ago and it was protected, so used an unlocker for deletion. BTW the ghosts are often hidden.
As it happens also to non-DO users, it seems to be a Windows bug.
Grin I know, I am in IT 
Then you knew that it couldn't be caused by a DO-upgrade :-p
It's a beta so anything is possible LOL
Ok, you won