Comment 7 for bug 1706008

Both PS1 and PROMPT_COMMAND might be relevant, they might change e.g. the window title (like PROMPT_COMMAND probably does), and changing the window title has a slim chance of triggering some bugs. You could experiment with setting PS1 to something very simple and also unsetting PROMPT_COMMAND at the same time.

Different bash versions might behave differently. 4.3 was an "odd" (read: buggy) one in the sense that it didn't handle window resizes immediately, only when a key was pressed later. With current 4.4 the prompt is redrawn immediately upon a resize, but apparently PROMPT_COMMAND as well as $() substitutions in PS1 are not run again. Maybe in 4.2 it used to be different and maybe PROMPT_COMMAND was re-executed or something like this, I don't know.

You could also experiment with running a "cat" or "sleep 10000" or "vim" or something like these (so that bash doesn't have a word during the resize), or using zsh (let us know if that's what you're already using).