Mini remote puzzle

I have a Bolt and 2 minis - bedroom kitchen. The bedroom remote had become very sluggish requiring repeated presses to go from function to function. I brought the kitchen remote into the bedroom and it worked perfectly. Also the bedroom remote worked fine in the kitchen - of course I switched them. But why? both remotes are identical - I checked out the part numbers. I put fresh batteries in both. When the bedroom remote is trying to do something on the bedroom tv and not working the light at the top that usually flashes orange or yellow, flashes red.

Mystery?