Xbuntu / AMD
Short description of error
A prop that's put into place via a copy transform bone constraint disappears until you hide and then unhide the collection it's in.
Exact steps for others to reproduce the error
Open up /scenes/01-opening/01_050_A/01_050_A.28.blend
...notice how the staff prop that should be in the character's left hand is missing...
In the outliner, hide the collection "Staff meshes"
In the outliner, unhide the collection "Staff meshes"
...notice how not the staff prop appears in the character's left hand...