bug n900 when downgrade from lollipop to kitkat help me please

hi im from iran and could not good speak english

im downgrade my n900 from lollipop to kitkat but sometime when lock it with power botton or auto lock after a few minutes the screen dont turn on again ...turn on just with unpluging battry and reboot...for example sometime in charging mod when the red LED is on or after fully charge and green led is on after hanging on sleep mod and unplug charger the led DONT TURN OFF and screen is off help me please