Interference from other wireless devices / power cables can weaken the signal. How it’s connected? There is extender included with the mouse, so you can put on your table and connect dongle to it, so it’ll be very close to your mouse.

When mouse is not working - do you hear any device connected/disconnected sound?

I just have the dongle plugged in on the back of my pc and my desk 15cm away from the pc. I’ll try the extender, thanks. 

There’s no device connected/disconnected sound. 

Issue still persists with extender, that wasn’t the issue. 

Does anyone have any suggestions? This is getting extremely annoying.

I’d try to test it in another environment (or at least different room), to check if it’s not interference problem.