I was unable to reproduce this in a different location, so it may be specific to that character / weapon. Or it may just be the characters I checked didn't actually use the equipment in their loot (sometimes there are two versions of an item with different stats/animations/size/etc, one for the opponent and one for loot for the playable characters).
Please email supportdos2@larian.com with your save there, where this can be reproduced (or a Dropbox or Google drive link, etc). If you are using any non-Larian mods, also include a list of those enabled and/or the modsettings.lsx file from your profile folder.
Each save is a folder in the '..\Documents\Larian Studios\Divinity Original Sin 2 Definitive Edition\PlayerProfiles\<ProfileName>\Savegames\Story' folder.
In Windows Explorer you can zip a file or folder by right clicking on it/them and selecting 'Send To | Compressed (zipped) Folder'.
