macOS has ncurses version 5.7 which does not ship the terminfo description for tmux. There're two ways that can help you to solve this problem.
Instead of tmux-256color, use screen-256color which comes with system. Place this command into ~/.tmux.conf or ~/.config/tmux/tmux.conf(for version 3.1 and later):
http://stackoverflow.com/questions/24380159/corebluetooth-and-wifi-interference
http://lists.apple.com/archives/bluetooth-dev/2013/Aug/msg00023.html
This is a well known issue, and it has a solution that is confirmed to work for the Mac side.
sudo defaults write /Library/Preferences/com.apple.airport.bt.plist bluetoothCoexMgmt Hybrid
After you run this script, the issue will go away and BT connections will remain stable.