Have you tried powering the thing off to see what happens?
No ... I never bothered ... as I was putting 'it/them' away for a bunch of weeks ... it was just as easy to pull the batteries. After reading your test results ... I just may experiment myself re: turning it off and leaving the batt in.
FWIW ... more on battery run down. So a recent P2.5 (just a couple-few months old) that's been sitting w/ an 18350 batt in it and powered on .. hasn't been used in a couple weeks .. when i picked it up and checked the batt ... it was 2.7 volts. Took the batt out and measured w/ a decent DVM - 3.1 volts. Put it back in the P and it showed 3.0 briefly then 2.7 and then the Led faded out.
Surely I need to test w/ the batt in and the P powered off.