Exact same here, we noticed it since we were competing with BlackLotus for 3rd spot.
My screenshot shows 4th place with 28400 points
One of my teammate's screenshot shows 3rd place for our coalition with 28725 points
Like @spadpl I always thought the games finished after boss death would add points to personal score, but not to coalition total
PS : please reduce boss health....
PS2 : obviously it is us who took 3rd place, Spad ;-)