I've found a very annoying bug with my Logitech Marathon m705 mouse: sometimes ( like 1-2 of 10 ) it misses wheel scrolls. That doesn't depend on whether I use hyperscroll mode or not. Neither it depends on scrolling direction. It is more likely to happen when mouse is on the move.
I've been using this mouse for 5 months and everything was fine. Yesterday I switched to another PC and now experiencing this problem. The main difference between PCs is that now I'm using 64bit version of Windows 7.
I don't know if this is important: I also use Logitech K350 keyboard with the same Unifying receiver.