I'm pretty sure it's a version + terminal + configuration issue.
I work in terminals all day long at home and work. I have a consistent user profile. On the other hand different operating systems have different terminals. I've seen the symptom occur locally (Ubuntu -> Gnome-Terminal -> bash -> tmux) and usually go away after an update of one of the components. But most frequently it occurs when crossing boundaries ({Windows, Fedora, Ubuntu} | {putty,gnome-terminal,tilix,serial tty} | tmux | literally anything). It happens more frequently when embedding tmux sessions while crossing those boundaries.
I _really_ wish there existed some software which would try to debug terminal display issues, even if it involved echoing something in a client program and then asking me "does this show up as intended and/or garbled?", with a timeout value for "it's so garbled that the user couldn't read or respond" similar to configuring a video display.
All the terminal emulators support xterm-256color and that's what the TERM is set to outside of tmux. The TERM inside of tmux (and ssh sessions inside tmux and etc) is `tmux-256color` as tmux is documented to want. I just wish I knew how to debug it.
I work in terminals all day long at home and work. I have a consistent user profile. On the other hand different operating systems have different terminals. I've seen the symptom occur locally (Ubuntu -> Gnome-Terminal -> bash -> tmux) and usually go away after an update of one of the components. But most frequently it occurs when crossing boundaries ({Windows, Fedora, Ubuntu} | {putty,gnome-terminal,tilix,serial tty} | tmux | literally anything). It happens more frequently when embedding tmux sessions while crossing those boundaries.
I _really_ wish there existed some software which would try to debug terminal display issues, even if it involved echoing something in a client program and then asking me "does this show up as intended and/or garbled?", with a timeout value for "it's so garbled that the user couldn't read or respond" similar to configuring a video display.