This happened at Aquaman’s party at 1:45 PM EST. Why didn’t the last box open? I already have the red Robo-Buddy. Shouldn’t I have received a charm or gems instead?
If the red robo-buddy was in the last box, you would have received a different prize if you already had that color.
This is a display error, but the prizes are handled on the 7 Seas Casino servers, so the prize would have been added to your account.
@Samantha Here is another “display error”:
I couldn’t even buy a charm and had to reload! 
(PARTY Buster BLITZ - Seafood Buffet - by coyotesan at approximately 9:40 PM EST)
This wouldn’t be a display error. It’s a loading error, and usually refreshing the page will fix it.
Okay, then it was a “loading error” this time. I did reload but missed the party. 
sadly it might be your internet server. i have the cheap 30.00 and it is sloooower..and when i called ATT they said well you arent the only one on that line.. I said what? they said yeah anyone in the neighbhorhood who has it, could be on it as well. i am already looking to upgrade my phone, (it was a donated one from a friend 2 yrs ago, because i wouldnt upgrade the one i had from 2017 hahah) so i might upgrade internet too..
Well, I just tested my download speed. It’s 488.70 Mbps. I think that’s pretty good.