I have found that after loading a multiplayer game, any item in my inventory when the game was loaded will not appear for my friends at all. If I stick it in the general inventory, they see nothing. If one of my characters dies, only I can see and loot the chest left behind. If I give a character to a friend, they won't see any of the items that character had equipped prior to game load. If they give the character back, I can still see the items. By some complex method of juggling characters back and forth and descending level, I was able to make one item visible to another player.

Hello Jerublius,

Thank you for your report, we are going to look into it!