xperia z3 compact unable to type letter `R` and digit `4`

HI,
This is Ashish , I have purchased Sony z3 compact in last month , I have updated it to marshmallow.
for one month all works good , I dont know suddenly how keyboard unable to type letter `R` and digit `4`.

I have tried all like update software, uninstall and install keyboard again but same problem persists.

please guide me. thanks