I just recently started having this exact same issue. I use it for video games. When using mouse look and scrolling on the 1st monitor it only controls the first monitor. When using mouse look or scrolling in and out on 2nd monitor it mimics the movement on the main monitor. I checked to see if I was broadcasting but was not.
Using the hotkey solved the problem for me. Thank you!
This has happened to me too recently. It's making the software almost unusable in some cases. Is there a way to bring the mouse back to the main pc if it's lost on another screen? Really need a fix for this.
I had a very similar problem on one of my pc's. The program worked great on 5 of the pc's but, one was super laggy. I found a solution by going in the laggy pc's mouse options (windows 10) > Additional mouse options > Pointer options > Select a pointer speed > set to whatever speed works best for you. This solved the problem.