One tag is dying or?

[lauri]

If the unit has been in humid environment for long times, it’s always possible that condensed water may have damaged electronics one way or another.

You could try to clean the PCB if you can see visible damages on it.

This topic is related and I can see that you already commented on it:

No connection at High humidity(temp)

The humidity may be creating a leakage pathway that drains the battery prematurely. I didn’t notice on the first one that failed, but on the one that I found failed today, the battery could only make 1.6 V. Another battery brought it back online. The tag was in-service in the ~100% RH incubator for maybe two months.