That's odd. I took an elevator four floors when I went to work today, AFTER upgrading to One UI this morning. My watch only records five floors, which makes sense since I live on a second floor apartment and ascended to it multiple times on the stairs. Maybe try rebooting your watch by holding the back button for several seconds? Note that this will not cause you to lose any data.
Without knowing how they do the floor measurement it's hard to say. It certainly uses air pressure changes, but I think the calibration only normalizes to your nearby sea level pressure to get the pressure -> altitude relation. Still, doesn't hurt to try!