When playing multiplayer, outside of using realms, on a local game. We have tested, several times, and this seems to happen with 100% reliability.

1. Host game on player 1's PC.
2. Connect to hosted game on player 2's PC using friends list from Xbox Live.
3. Player one presses ESC and selects "Save and Quit"
4. Player 2's game will crash.

This is probably simply an unhandled exception where an error message should be displayed, but at the moment it is a full application crash.