When did you get donate for the feature that pushed you over $50? What features do you have?
In game tags are instant, forum badges take 1-7 days to be updated.
As well, in game, [$$] is $50-$99, whereas on the forum the slimeball is $10-50. This means that if you have exactly $50 in features, you'll have the forum slimeball but [$$] in-game.

Remember you can use /mydonations to check which features you have.

 

Water = $15
TPA = $20
Multihome = $15
---
Total = $50

 

That explains why I have that also

 

psst one of your tag examples still says