The Fairy Collector achievement which requires each of every fairy in my inventory is not working, I have all the eight fairies in my inventory and I've tried refreshing the inventory page and all.

If you have all 8, then try going to the achievement in the Luminaire section and click the "Show items" button to trigger it.

I've also been experiencing this issue. I also tried doing "Show items" but it didn't trigger the achievement, all the Fairys are still red as though they are not in my inventory.

I got the achievement somehow, think it triggered when I clicked "show items".

Somehow the achievement triggered, although I didn't get a notification for it at all!

Here is a screenshot of my inventory (sorry it's cluttered):

This is what the achievement looks like now. I still have all of the fairies in my inventory:

I wish I took a screenshot of what it looked like before the achievement mysteriously triggered, it was basically the same but all red and it wouldn't acknowledge the fairies in my inventory.

I am just glad it triggered! Just seems a bit delayed.