Walls are not forming.

I though it was only me.... but I've confirmed that other players are also having the same experience. Wall just doesnt show or somehow fails to be made the next turn.

Yup on casual i have often that problem

Yes, i've been having this issue on casual games especially. Quite frustrating.

Usually you need to go back into the game again to confirm that the walls have formed... and you need to be really careful to not put them near any other unit or they will unite as well as if you put the unit too close to your city, it will go inside