Thanks John, I'll try to power cycle. Other than that, while I appreciate your suggestions, they strike me as far too fiddly. I expect the remote to simply work, w/o any special steps or considerations like power cycling every time I use the amp.
I think you may have misinterpreted my response.
I am not aware of a single other event as you describe by any other users, and the one I experienced was "only once".
So, if your issue is continuous, then it is likely a "one off" malfunctioning unit, not a normal one.
My suggestion was a "try this" suggestion, since I have seen processors in AVR's, Bluray Players, Streamers, Servers, and other more sophisticated components, on occasion reboot to no further issues.
In these cases, there could be any number of causes, like temporary power failures, stray IR signals, voltage spikes of drops, etc.
My suggestion to "power down" when not in use, was under the possible issue of powerline or voltage vacillation, that could be the problem. If power stops or drops, it is like turning your computer "off and on" quickly so the the reboot fails.
If your unit doesn't respond, or continues to be "fiddly" it should be looked at and repaired.