Bash Zsh – Bash Throws ‘set-ena’ When Pressing ‘b’ in Terminal

I have an extremely weird error:
when I write the letter b in my terminal, bash immediately starts to write/throw endless stream of "set-enaset-enaset-enaset-enaset-enaset-ena…" until I force it to stop, by Ctrl-C, or exiting bash. I have removed my .bashrc and replaced it with a default one, but it didn't help. I have also purged bash, and reinstalled it, and also it did not help. Interestingly, when I use my zsh in the same terminal, it works without this error. When I use bash not in the terminal programme, but simply in ubuntu text-mode (console) the error also happens.

When I copy-paste the letter b it also happens. I should note, that it's not required to write b and press enter, the stream of "set-enaset-ena…" starts even before I am able to press enter.

EDIT: I disovered that when I enter the command: set -o vi manually then it's not broken anymore (until I enter set -o emacs. However, when I tried to put set -o vi into my .bashrc, then it didn't work, and actually I had to switch to emacs mode this time for it to work.
Strangely, changing the mode manually, from whatever it was before to something else fixes this weird problem