Screen sharing drop-down/menu issues

I have a unique scenario where we are running off old software that is stuck on Mojave. To mitigate security risks and get everyone up to date, I setup Mac minis that everyone remotes into, via the macOS screen sharing app, just to access the software in question. The issue arises when two or more people log in at the same time. Mac supports up to 5. Each has their own screen sharing session. But there is a 50/50 chance someone logging in will have an issue with drop downs and menus that don’t stay open. You need to click and hold to keep the menu open and release on the item you want. You can tell these issue will happen immediately because there will be a second cursor locked to the top left of the screen. These are the troubleshooting steps I tried. - unplugging mice and keyboards from the Mac mini - using Ethernet and WiFi - logging out and back in as a different user (issue is present the whole screen sharing session no matter the account logged in) - restarting may only temporarily fix the issue - one thing that does stop the menu issue is logging into said users account locally on the system and moving the physical mouse. Then the screen sharing session for that user doesn’t have the problem. Has anyone experienced these issues?