On my Mac, if I command-tab away from MC and then back, the regular mouse pointer will persist on the screen. It's usually somewhere other than where the cross-hairs are.

The full-screen mode I'm using is the native one (using the little green orb on the window). If I use command-tab, the mouse pointer will stay on screen. This didn't happen in 1.11, but it's (as far as I can see) 100% consistent in 1.12 snapshot. To get the problem to go away, I have found that using the three-finger swipe to switch desktops and then back will fix the problem.