♡ 77 ( +1 | -1 ) No ...I don't have mobile broadband and have not experienced it here at all. It would be interesting for you to see if it would happen to you on other sites, especially if they use a program like TimeSeal which is supposed to disregard the transmission time when debiting your clock. Such as Chessanytime.com chessanytimecom does. I have had time loss on two other sites tho, while it was my move. But the clocks there and connections too, were not very reliable at all. One of those sites also knocks you out of the blitz room about every third game, if they get more than 60 games going. The other often forfeits you when your clock still has even 10 or 12 seconds showing on it.
♡ 21 ( +1 | -1 ) ...It's a lag issue. Even though the clock appears to stop when you submit a move, it actually keeps going until the move is fully processed by the servers. If you have a solid connection, it won't happen.