Magic Mouse arrow briefly gets stuck at random places on screen
I have found that sometimes the surface you're mousing on can have surface qualities that alter the reflectance of the mouse's IR beam and this can affect the cursor behavior. Study the mousing surface to see if any part of the area that maps to the screen has a change in color or texture as this can contribute the the behavior you're observing. 

Otherwise, you can try to reset your mouse by unpairing it, removing its batteries (if its an older Magic Mouse) then reseating the batteries &amp; re-pairing again with your computer.