Ok, thanks. Next time side buttons stop working will try to get the log. Sadly is something "random".
Probably, as Corsair Henry said, is something that only occurs to a handful of users and it's difficult to trace. But it's very annoying.
Could be a hardware incompatibility, or perhaps something about habving other USB devices connected at the same time the mouse is connected. Let's see if the engineers could track this issue and solve it.
If not... time to change mouse... :confused: