Default [Q] back key & recent key not working in xperia ray

After flashing xperia overlay..around 2-3 days later my back key and recent key suddenly stops working.
I thought it was minor issue so i just flashed the stock firmware but issue not solved.
then i again root my device and try some onscreen keys application..but it also not worked.

what happened to my wasn't wet, dropped or anything else.

Xperia ray st18i
Sony Xperia M C1904 Rooted/Unlocked Bootloader
Unofficial AICP
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