Not sure if you have an issue, too many variables but temp and altitude are not factors in this scenario. I don't fret minor DC voltage fluctuations, and I don't always rely solely on what our solar charge controller, EMS, or my multimeter indicates as it pertains to battery health at any given moment in time.
I find it prudent to have a genny when RVing off the grid, along with our fast charging smart converter I know I can restore amphours into our 12 volt reserves should the need arise. Not parking under trees, RVing in cloudy weather, or just barely using our rig's amenities to eek by are things we have long had to worry about.