KoBeWi
Jumpkin
I played multiplayer again. We went to to the last phase challenge in Mount Bloom. My brother couldn't finish it so I told him to leave and he'd rejoin in next room. He joined on the ledge at the entrance. I recorded a lengthy and boring video about his attempts to jump down 
Important moments:
0:03 - he used Titan Throw (before video started) and lost weapon. At his side of course, for me, he appeared glitching around. He couldn't retrieve his weapon.
1:06 - he used Protect, so his proper animation got restored. He now jumps down and teleports back few times. On his side, he never left the ledge.
1:46 - he used Frosty Friend. It appeared down. But on his side, he still was on the ledge, so his summon appeared on lower floor for no reason from his perspective.
2:22 - he shoots few arrows, because why not. Arrows go through wall on upper floor.
2:39 - end of "interesting" stuff
Important moments:
0:03 - he used Titan Throw (before video started) and lost weapon. At his side of course, for me, he appeared glitching around. He couldn't retrieve his weapon.
1:06 - he used Protect, so his proper animation got restored. He now jumps down and teleports back few times. On his side, he never left the ledge.
1:46 - he used Frosty Friend. It appeared down. But on his side, he still was on the ledge, so his summon appeared on lower floor for no reason from his perspective.
2:22 - he shoots few arrows, because why not. Arrows go through wall on upper floor.
2:39 - end of "interesting" stuff