The remote for my Sherwood Newcastle R-772 frequently loses contact with the receiver (i.e., button presses do nothing). Momentarily removing a battery from the remote cures it, though sometimes I also have to power the cycle the receiver.
Sherwood verified the problem using my remote and their test receiver, so they sent me a new remote under warranty. Excellent! Except that the problem remains. So apparently it can't be either a bad remote or a bad receiver.
I use the remote in RF mode, case that makes any difference.