After you complete the 4 trials, you have to go to Artisan Poppuri in Moss Cave. He will ask for Trickster Crest (which is given by Fairy Nono after completing the 4 trials) and 5 Harkon Shards. After that, go back to the fairy and you're done!
Yeah, maybe a screenshot will be more clear...
I've completed all 4 trials, and did receive all 4 crests at one point, I talked to Fairy Nono, but for some reason still did not give me the trickster crest. I relogged, and only the Love Crest is there, the other 3 disappeared (see image).
I can enter into the 4 trials, but they say that I've already completed it, meaning that I can't obtain the other 3 crests.
Anyway to contact a GM or someone on this?