Chat log automatically typing same letter (PS4)

Was just playing as normal and then suddenly (during a cutscene) my chat log activates automatically and keeps spamming 'f' or 'g'. I have tried turning off auto-chat etc. but this does not help the issue. Tried restarting too. Nothing is working. It will do the same thing if I go onto the controller's keyboard input too.

I checked on the PS store (search) if it was doing it there and it wasn't.

Edit: Never mind; figured out my external keyboard seems to causing the issue.