After installing KoReader via the one-click package, I lost the "O" in the german keyboard layout in Nickel. If I tapp it, it just shows an empty space. Fw 4.18.13737 on a Libra H2O.
I tried a factory reset and got my "O" back. After installing KR the "O" disappeared again.

The keyboard layout in KR is fine, the change affects only Nickel.
A w rld with ut an "" seems like a l t f fun, but ... I want it back, as s n as p ssible. ;-)