Ring app does not accurately reflect battery charge

I set up my new Stick Up Cam Solar several months ago (around end of May); it worked so well that I got a second one shortly thereafter. In the full Hawaiian summer sun, app initially showed batteries for both cams consistently charged at/near 100% every day. A couple of weeks ago, app started showing batteries slowly draining to where it has held steady at about 86% (1st cam) and 93% (2nd cam) for the past week – despite switching off “Record Motion” for up to a day at a time (both cams).

Fearing the worst, I just purchased a backup battery and ordered a Super Solar Panel through Amazon. Now, after seeing similar experiences described in various community posts, I’m thinking that the issue may not be with the hardware.

Ring app ver. 3.30.0; Android 10 on Galaxy S10.