Once the built-in battery reaches its discharge limit, the keyboard input is a gamble. Letters bounce, depressed numbers appear in several ways. Too bad if the one happening in online banking. Anyway, I was annoyed several times about this effect. The custom key assignment function was also unhelpful or worked poorly (eg sluggish response of the volume slider) Have the part relegated after one year service life in the area and recommend to more established products to keep an eye out.
