Continuity mistake: The shape of the staircase in the living room is slightly different to the original one. In Full House, the lower half of the stairs before the midway landing was shorter (roughly 5 steps) and the upper half was longer (about 7 steps) where as in Fuller House, the lower half is now the longer section (about 7 or 8 steps) and the upper section after the midway landing is shorter (roughly 5 steps).
Continuity mistake: When Full House started, it was stated that D. J was 10, Stephanie was 5 and Michelle was a baby. The Tanner girls were five years apart but in Fuller House, Stephanie says, "I'm 36", in response to an old lady calling her older than 50. But, D. J's 40th Birthday is not until the next season. D. J was still 39 at the time so Stephanie couldn't have been 36 or else D.J. would have been 41. Also, DJ's 39th birthday is in S2 and her 40th is in s5?
Continuity mistake: In the original Full house, there was a closet in the room that ended up being DJ's but that closet seems to have disappeared in the Fuller house episodes when they show what is now Tommy's room.