In Firefox on Android, I can't type a secondary character (e.g. "p") as first character into the address bar. Double tapping y/p results in "yp" instead of only "p". It works everywhere else, but not in this specific text box.

Also, somewhere in the docs it's mentioned that you can use one of the outer buttons as trigger for a secondary char (i.e. quickly tapping "o/y" should result in "p"). I couldn't get this to work even once.