What model BMS is it? Most can have their settings adjusted.
Better to measure current into the battery to see what’s happening around 48v. You can 3d print a case for one of those DC display meters and put it in line with the charger. Really helpful to see what’s going on. There is a whole thread on it:
I used to charge to about 4v per cell just to give the battery some more cycle life, and range was still really good. Probably 80% if I had to guess.