'back' Navigation Button Stops Working

Apr 11, 2016

I got my Redmi 3 some days ago (with the xiaomi.eu stable rom included) and i've got a probleam concerning the back button (the one on the right). When i click it multiple times it just stops working - i have to move it or wait a few seconds until it starts working again.
My question is, is this a ROM bug or is the device faulty? Should i send it to warranty?

Thanks in advance.