Thieving in general gets half fragments (these are still doubled from the bonus).
However, Shifting Tombs will give you the highest amount of Fragments!
This thread was added on August 16, 2019, with posts from Shaunyowns.
Original Post
https://www.reddit.com/r/runescape/comments/cr63pz/bug_camouflage_fragments_are_currently_not_being/