It's possible this isn't a bug, but I noticed something funny about my achievements. I'm a long-time player returning from a fairly long hiatus, and some of the achievements I've earned (from way back) aren't listed as such. Some have since retired while others that are still available are showing as 1/1 without being unlocked (see screenshots). Is there a way to trigger en mass all that's missing?

only thing I can think of, is to file a ticket for something like this

you can also try hitting claim titles. It's the third button down on the left under search on the achievements page. It might jiggle something loose lol

I just completed 2 plushie groups and did not get the achievements. Candy Corn Cuteness & Environmentalist. I have refreshed several times, and also clicked on Claim Titles. No luck.

Have you gone to the actually plushie collection?