Fixed it!
Finally I was able to fix it and it was because of improvement of UIButton
behaviour in iOS 7.1.
They just started rendering round-rected shape filled with tint color when UIButton
is selected.
It was semi-transparent one in iOS 7 and I remember that I put clear color just to make the buttons clear to see. That was the issue and they rendered transparent rectangle around the buttons and we're unable to see anything when selected at all! Hope this would help others who have the similar issues.