I am using the button on top of the mouse as play/pause button. However after not using the mouse for a while it enters some kind of power saving mode and temporarily forgets the assigned functions.

So when I press the button on top is disables ratchet mode and enters free spin mode. After that the mouse uses the assigned button functions again, so it performs the play/pause action and I'm stuck with a free spinning middle button, so I have to go in the settings to revert it to ratchet manually. Very annoying bug.