RasPi 3 GPIO input not stable [Hassbian]

I am new to HASS. I basically want to play some music and switch on some 7 segment display when a pushbutton is pressed. Everything works fine. However, sometimes the pushbutton (PB) status is not reflected. i.e. OFF->ON-> ON (Doesnt come back to OFF, once the PB is released). This happens at about once in 10 times. I installed WiringPi to check if the status is read wrong, however the status is correctly shown in gpio readall. What are the workaround? What is the mistake? Is an experimental version or an older version fix this problem? I use RasPi 3.

I tried various combinations: pullup, pull down, bounce , etc. I changed the input pins, etc. but doesnt help.

I can post the config and automation code if required but I do not think there is anything wrong with that as it works 9 out of 10 times correctly. Please help. I have a deadline