With my mixed bank of beat up (previously enjoyed) two 12v T-1275s and four, three- year old 6s, when full and on shore power Float at 13.8v regardless of ambient temp ( I do everything according to the battery rules! :) ) I get accumulated AH showing on the Trimetric way "over" supposed full after a time.
After almost a week this can get to be near 100AH "over." I just ignore it all and reset the Trimetric when I start camping off grid again.
I suppose it is the beat-up T-1275s themselves which never manage to get truly full or else some interaction between them and the four 6s (which are also of two different brands) or even between the two 12v batts among themselves.
Whatever, there is no rest for those amp electrons! They keep working at it, jacking up the AH figure way past Full.