My mouse started acting weird right after my computer updated from Windows 8.1 to Windows 10. I know that "weird" isn't a technical term, but it seemed to have a mind of its own, stuttering and bouncing all over the screen.
This keyboard / mouse combo was only a couple weeks old, so for a while I was wondering what the heck was going on. The keyboard would also randomly stop working. It was really frustrating until I noticed that it was worse when I was transferring large files.
Eventually I figured out that it doesn't like being plugged into a USB hub in Windows 10! I have no idea why it didn't do that with the same hardware and plugged into the same hub under Windows 8.1, but I didn't have any issues.
Maybe Windows 10 has a different USB driver or something, but I moved the dongle to a different USB port and haven't had an issue since.