Move not registering.

I've only been on this site for about a week. Twice I had a case where I'd make a move, but my clock would continue counting down. The first time it happened I had a good position, I spent about a minute and half trying to figure out why my clock was counting down. I offered a draw with 30 seconds left, the moment he declined the board reset to the move before, then in an instant without touching anything my move was made. I somehow ended up winning anyway.

The second time it happened my position was completely winning, so I was afraid to offer a draw, so I offered a takeback move and luckily my opponent was kind enough to accept.

I want to prevent anything like this in the future, any ideas?

Reloading the page (F5) should work in most cases. (it depends on the exact problem, but F5 rarely hurts ;))

Thanks, I'll try that next time :)