I had ended the previous season with seasonal mods in the artifact mod slots of my artificer armor, and now those pieces of armor are missing those slots. The affected armor pieces are: Twisting Echo Mask Twisting Echo Vest Twisting Echo Cloak All three of these are artificer armor, but are somehow missing their artifact slots. Edit: I just checked the pieces of armor in Destiny Item Manager (DIM) and the slots don't even show up there, but in both places (DIM and D2) they say they are artifice armor pieces.