[txr]

The assumption from the forum discussions is that it has nothing to do with other AirTags as the battery goes back to normal when people remove their AirTag.

I had the tag on my bike which is the basement so 3 floors down. It just barely reached it from my bedroom, still very impressive. The assumption is that it has something to to with the tracking prevention where the iPhone is somehow telling the AirTag that it is still in the vicinity. If the AirTags is at the edge of the receiving/sending radius this might need a lot more power. Maybe due to retransmission, etc and therefor for causes my battery drain over night.