[joeshaw]

It appears so. Probably worth filing a bug about this, but I suspect that something about mosh's terminal emulation filters out the VT100 command sequences tmux uses to perform the handshake with iTerm2.

Details on the protocol are here: https://docs.google.com/document/d/1ABI0kqUUxoAjxhWW3AsWFis6...

[mooism2]

I expect it would require explicit support from mosh.