I have a mac pro and mac mini on the same network both signed in with my apple id. File sharing was off. When I copied files from an external drive to the mac pro, a message shows up (with some delay) on the mac mini. 

This led me to believe initially that someone out there was taking control of my computer since I copied nothing to the Mac mini. After a few experiments it seems that this is coming from Parallels Tools interaction with Universal Clipboard feature of Sierra and Catalina. Can someone else confirm this hypothesis? This would seem to be a bug as it is a bit alarming to see messages about files being copied that I did not initiate. Why is the program behaving this way? Will it be fixed?
This led me to believe initially that someone out there was taking control of my computer since I copied nothing to the Mac mini. After a few experiments it seems that this is coming from Parallels Tools interaction with Universal Clipboard feature of Sierra and Catalina. Can someone else confirm this hypothesis? This would seem to be a bug as it is a bit alarming to see messages about files being copied that I did not initiate. Why is the program behaving this way? Will it be fixed?