A patch for this is now available in the upstream bug tracker (https://github.com/tmux/tmux/issues/1861) and I have tested it successfully using the Mutt recipe from #933572.
- Bug#933514: tmux: Screen garbling in ncurses apps T. Joseph Carter
- Bug#933514: tmux: Screen garbling in ncurses apps Romain Francoise
- Bug#933514: tmux: Screen garbling in ncurses ... Sven Joachim
- Bug#933514: tmux: Screen garbling in ncur... T. Joseph Carter
- Bug#933514: tmux: Screen garbling in ... Romain Francoise
- Bug#933514: tmux: Screen garblin... T. Joseph Carter
- Bug#933514: tmux: Screen garblin... Johannes Stezenbach
- Bug#933514: tmux: Screen gar... Romain Francoise
- Bug#933514: tmux: Screen garbling in ncur... Romain Francoise
- Bug#933514: tmux: Screen garbling in ... Sven Joachim