Thought I had gotten a bad batch of batteries because no matter what I did, I couldn’t get an AirTag back online after a replacement.
Turns out, the bitter coating seems to be preventing proper contact in the AirTag. Cleaning the battery off with an alcohol swab solved the problem immediately for me and my AirTag came right back online.
Did you buy your copies pre-licked?
Maybe there’s someone at the factory licking the cardtridges before sealing the boxes, and I just happen to be getting the pre-licked ones.