Saying "I am facing the same problem" implies that there is a problem. This is equivalent to someone on a car forum saying "Whenever I get up to speed driving forward and then try to shift straight into reverse, I get a grinding feel."

There is not a problem. As the responder in post no. 2 said, derailleur-equipped bikes are not designed to allow backpedaling.

Don't backpedal. "Problem" solved.