Trading adds/subtracts from NPC max volume/weight weirdly

[molkero]

Describe the bug

Trading stuff from NPCs affects their max volume/weight in the trade screen, so that they can go negative volume if you take items from them.

Steps To Reproduce

Steps to reproduce the behavior:

1. Find and trade with an NPC.

Expected behavior

Taking items from NPC would give them more space, giving them items would give them less space.

Screenshots

This NPC has 2,5L of storage and a 2,5L canteen. Taking the canteen makes him go from 0 volume to -2,5L. Giving him stuff also gives him more available volume and weight.

Versions and configuration

• OS: linux
• Game Version: 0.D-8418-g126c27ba3e
• Graphics version: tiles
• Mods loaded: [ "dda", "mutant_npcs", "boats", "blazemod", "Tanks", "sleepdeprivation", "cbm_slots", "magiclysm" ]

Additional context

Noticed this because my NPC friend is a bear and can't wear much other than an XL jumpsuit with not much storage.

EDIT: Propably not related, but every time I visit the trade screen, I get a message "NPC drops a ." in the log.

[ANickelN]

Trading is borked right now, this is probably related to the game crash when trading at refugee center.