Steamworks - Problem with GetLobbyMemberByIndex

We're using Steamworks.NET and have run into a problem with results seemingly being cached. Specifically around index of players in the lobby (SteamMatchmaking).

I set up a 3 player lobby, with player A, B, & C, where A is the creator and B & C join in that order, and then have B leave.

Calling GetLobbyMemberByIndex and comparing the steamID with the local user steamID on each client at this point gives me 2 players in the lobby, with player A still at index 0, and player C now at index 1.

If I then have player B join again then both player B and player C are now at index 1 in the lobby. Player A and C both think C is index 1 and B is index 2. But B thinks he is still index 1!

Anyone run into this with players rejoining lobbies?

 

I am having the same problem, I'm cracking my head open trying to fix that.