Psychopath
That guy with the shoebox.
I've noticed it happen a few builds ago when being command-grabbed by Beowulf but initially wrote it off as a visual error, as the shadow didn't disappear until the end of the grab. However, today I was grabbed by Squigly while holding an item drop, the shadow remained active. I released the held key during the animation and the item itself dropped from the sky once I recovered from my ground tech.