I have a late 2014 Mac Mini and am having problems with my wireless mouse. I have used both a magic mouse and a Logitech mouse and the problem is the same. The mouse works fine for a short while and then the mouse pointer gets stuck momentarily. It still moves but jumps from position to position on the screen as it tries to catch up to where it should be. After a few minutes the problem goes away and then a short while later it starts again. I think it is a problem with the Mac Mini because the mouse works fine with my macbook pro. A few other facts:
A wired mouse works perfectly fine.
I replaced a Magic Mouse 1 with a Magic Mouse 2 - this didn't fix the problem
I then purchased a Logitech wireless mouse with the dongle (i.e. not bluetooth) - this didn't fix the problem.