Just to be clear, I assume you're talking about K256AE - the 99.1 that normally carries Easy 99.1 in the Salt Lake County area, right?
What you describe seems like pretty good proof that (at least when this happened) K256AE was using an off-air feed. Surprisingly I've heard of this sort of thing happening before. I don't know if this is what happened in this case but it's an amusing story nonetheless. There was a station that was an in-town relay of a distant station. The off air feed was from an off the shelf consumer radio that was hooked to the transmitter. Unfortunately the cleaning guy who was hired didn't know this. He didn't like the music that was coming out of the "radio" so he changed the station....to the compeditor's station that was running the same format. Whoopsie. I'll bet they put a big sign on the radio after that one.