I had approximately 30 siva key fragments in my inventory yesterday and had zero when I logged back in today. The only notable thing I can remember is that I helped a group at Vosik and there, the Siva Key Fragments drop as small white mini-engrams and one fell off the map before I could even get to it. I refreshed DIM and it did show that the key fragments went to my postmaster. This happened yesterday. I do not believe I ever ended up retrieving the fragments from the lost items yesterday. Today, they were not in the postmaster and I have lost around 30 fragments that I had stored in preparation for tomorrow's weekly reset.