That includes its ability to return to the wielder when thrown. I just tested it out and the weapon came right back (so I would assume that the disarm immunity applies, too). Seems like that might be useful for a throwing barbarian build (tavern brawler, throwing ring/gauntlets, etc.) and I wanted to share. It’ll probably get patched in the future, but I haven’t reported just to see if anyone can come up with something broken.
You can use withers to create level 10 clerics and they reset levels when you return them so you can have access to infinite divine intervention and thus have access to infinite legendary maces