Try a dumb-sounding thing. Hook your telephone test set -- butt set -- across the IR signal line. It should be silent if no commands are being issued.
I once found a noisy IC in a dinky linnk this way. Don't ask why it occurred to me to put a butt set on it. But once I heard it I knew why IR wasn't working correctly. There's nothing that says a problem can't develop after a year. And it could be an RP1 problem that doesn't show when the RP1 is issuing commands, only when it is silent. Or supposed to be.
A good answer is easier with a clear question giving the make and model of everything. "The biggest problem in communication is the illusion that it has taken place." -- G. “Bernie” Shaw
