The dang thing has been rarely doing the 3 chirp code a couple times during the day for the better part of a week now. Our cat is really frightened by the sound and I fairly quickly had a suspicion which one was throwing the chirps but I couldn’t catch it in the act to be sure, and it was otherwise ambiguous which one was at fault and there were no LED codes to help.
Finally confirmed it today. 10 years and 1 month past date of purchase. 10 year warranty. Figures.
In my case I did a round of battery replacements about a year ago to get them all synced after a couple annoying staggered battery replacement chirps, so I’m familiar with the codes. There was one of these that did the 3 chirps late last year and I got that warrantied successfully, so based on that experience I went ahead with replacing this one.