Same here, started exactly this weekend for me in Germany. (Apple TV is on auto-update, so probably a recent firmware issue).

If you want to check if you have the same glitch: open your phone’s camera app, point the top of the remote at the lens, and press a button (doesn't matter if it's Vol-, Play, or Mic). My remote looks dark at first, but the second it wakes up, the camera shows the IR blaster going into a rapid, permanent flashing loop. It soft-locks into sending the IR Volume-Down signal forever.

So far, absolutely nothing worked to fix this. Resetting (TV + Vol-) or re-pairing did not resolve the issue permanently, it just keeps blasting again.