I have 857 plushies in my collection. I went to the achievement page to see how many I had left until the next tier. Here's what it says:

Plushie Collector (1% of users have this achievement.)

Collect 700 Plushies. 611/700

It's been stuck at 611 even though I've added more plushies in the past hour.

Go to your plushie collection page. It should update then. Pretty much all the collections work like that, for future reference. c:

Nope, still isn't working :/ I just tried that, it's still stuck at 611.

Hmm, well I'd heard a while ago plushies were having problems, but I thought it had been fixed. Looks like it's broken again. Sorry I can't be of any help. ^_^;

It's okay, thanks anyway :D

EDIT:

Oh dear. I figured it out. You have to go to the Prizes page and the Achievement will update.

This can be locked :)