I honestly never noticed that before with my phone. What I mean is that I never paid close attention so not sure if it happened or not.Did you ever notice when updating your cell phone with a new OS that battery life drops for a day or so? This is because the processor is doing extra duty to reorder/reindex and clean up files post update. Could be the same thing doing in with our cars. See if things change in a day or So and report back.
Also, the phone doesn’t tell me I have X number of hours left of use so even if the charge changed, I wouldn’t know.