Hello people of /r/HollowKnight .

I got addicted by this magnificent game during these Christmas holidays, but I seem to be unable to complete the game. I discovered all the map, picked all the upgrades, bought anything, finished the Grimm Troupe DLC, met Mr Mushroom in all the places, I just need to end the game... and find the last Mask Shard... which is impossible, because I picked all of them up and yet I am still lacking ONE damn shard.

I double, triple and quadruple checked and I made an album of all the locations, that I also looked up on the Wiki and the videos, still...

Mask Shards 1-to-4: Sly (he tells me I bought everything I could from him and gave him the key already)

Mask Shard 5: Bretta's house in Dirtmouth

Mask Shard 6: Grubfather (he gives me a shard after 5 Grubs)

Mask Shard 7: under the False Knight, where the Goams are

Mask Shard 8: Brooding Mawler, killed it

Mask Shard 9: beated the Crystal Guardian twice

Mask Shard 10: brought the flower to the kid's tomb and the Grey Mourner gave me a shard

Mask Shard 11: Stone Temple

Mask Shard 12: Queen's Station

Mask Shard 13: Deepnest, near the Mantis Lords left exit

Mask Shard 14: the Seer gave me one after 1500 essences (I got 3000 and over and the lady is long gone)

Mask Shard 15: Royal Waterways, NW room, after the water corridor

Mask Shard 16: the Hive

So I got all of them, yet my inventory shows THIS
Did I went to the wrong places? Am I missing something? Please help a desperate guy.

PS: sorry for the picture's poor quality, I had to lower the quality to be able to load all of them in the 2MB size limit