Party member with vampirism is subject to crashing when the party leader appears in their cell

[miredirex]

Version of Skyrim Together

dev branch, v1.6.7, v1.6.5

No additional mods, only the required ones

Description

When a party member (guest) has a status of a vampire lord, there's a very high chance they might crash when the party leader loads into their world (basically when their NPC character appears). Even if the guest is entering cells last, they could still crash. The player's active form/transformation doesn't matter, crashes occur in both human and vampire lord forms

Steps to reproduce

This can be reproduced on a fresh pair of characters right after Helgen. You can either get vampirism naturally, or via console commands. For simplicity's sake I'm going to use console commands

1. Connect to the server as character A
2. Create a party as character A
3. Connect to the server as character B
4. Make sure you're in a party
5. As character B, enter player.setrace yourraceracevampire (for khajiit it's player.setrace khajiitracevampire, for nord it's player.setrace nordracevampire, etc.) and player.addspell 0200283b to get the spell
6. Transform into a vampire lord once, then return to human form (I'm not sure whether this step can be skipped, but do it anyway)
7. Now as character B you can just stand still and do nothing for the rest of it, just make sure to be nearby
8. As character A (the party leader), start going into and out of interior cells (entering different houses) until character B crashes. This can take over 10 attempts. You'll have a better chance of crashing in crowded cities like Whiterun

The most common crash sites are 0x140443C43 (stack leads back to HookPerformAction) and 0x140231AF8 (stack leads back to EquipManager::UnequipAll), but these are not the only ones

Reproduction rate

I'd say 60-80%

• 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

No crash

Workaround

Cure vampirism

[miredirex]

#725 fixes 0x140443C43, #726 fixes 0x140231AF8