Erratic magic animation sync #680

Version of Skyrim Together

1.6.5

Description

Remote player's magic casting animations sync erratically. Sometimes their arms will raise, and sometimes they won't--in which case the magic will still fire, but their character will retain the magic out idle animation.

If casting with one hand, sometimes the other hand will also go down entirely to the player's side, as if they didn't have their hands out / were casting whatsoever.

Steps to reproduce

1. Connect and join a party as normal.
2. Have remote player cast magic so you can watch them. (Specifically, flames is an easy one, as it is concentration.)
3. Make sure they try casting on and off, on and off, repeatedly. Holding magic in both hands makes it easy. Their hands will raise only some of the time.

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Reproduction rate

• Consistent: I can reproduce this bug by following the steps to reproduce 100% of the time (every time)
• Occasional: I can reproduce this bug by following the steps to reproduce around 50% of the time
• Rare: I can reproduce this bug by following the steps to reproduce around 10% or less of the time

Expected result

Evidence (optional)

https://media.giphy.com/media/v1.Y2lkPTc5MGI3NjExb2FqN3VwOHR3bWJ3eDI1ZDg4bGpxdXo3cTR5ZDV3djBtZmJscG15dyZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/5s0Wc1SWFXYnAtjdFc/giphy-downsized-large.gif

Yes, this evidence is from the Alternate Start cell, because it made it easy to test w/o coc riverwood. SKSE is not enabled, and it is reproducible irregardless.
EDIT: just tried without ANY mods just to be sure, and the issue persists.