Party members floating/sinking while on moving platforms

Party members are not moving in synch with lift/elevator platforms. They move up and down oddly, sinking into the floor or floating above it. This seems to have started in patch 5.1.

Multiple people have experienced this bug, and it seems to happen consistently.

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Date & Time: since patch 5.1 released
Frequency: always?
World name: various
Character name: various (I have personally seen it on three different characters, plus other people's reports)
Retainer name: n/a
NPC name: n/a
Monster name: n/a
Class/Level: any
Party or solo: party
In-game time: any
Housing: n/a

Areas:
- Copperbell Mines
- Aetherochemical Research Facility: Triad Control
*** however, NOT the Aetherochemical Facility Autolift, which seems to be a moving platform but it's in its own zone, and I would guess that maybe it's actually a static platform with moving walls and not vulnerable to the glitch.
- Sunken Temple of Qarn - no lifts here, but I think I saw someone sink into a staircase as we were running up it.
- "MSQ roulette" as described in the linked post - presumably the Praetorium.


Steps:

1. Enter a dungeon

2. Ride a moving platform up/down

3. Notice that party members are jerkily moving up and down, sometimes halfway into the floor and sometimes floating above it.


The easiest place to see it is Copperbell Mines since there is a lift immediately after the first group of enemies.

I can provide a video if for some reason it cannot be replicated when testing.