AirTag drains its own battery very fast (replacing every month)?

I've got a feeling I'll end up needing to visit an Apple store for replacement, but has anyone else found an AirTag to drain its own (CR2032) battery within a month?

I got a 4 pack very end of May, and now by end of July I got a second "battery is low" notification for the same tag after I replaced it once already. The other 3 are all around 75% or higher. I already did the '5x battery remove and replace' to reset the tag but it hasn't made any difference.

Seems to be lots around on AirTags draining phone batteries, but can't find anything on them draining their own.