I got that too! Wtf?! Plus i was pretty sure i had posted more than 9 times that day, which i dont usually do, so i took it pretty personal!
Facebook groups have a daily post limit, maybe they are trying out a similar rule. But obviously just on their favorite customers!
ETA - WOOPS! I just lost gif! I mean, i had one, then i added it twice, so i deleted them, now gif is gone.