Play Calls

I run plays since it helps with scoring. I will call a play and everything runs smoothly give the floor indicators. But other times I can the play in a similar situation and the players just stand around in place and none of the floor art shows up.

Am I doing something wrong or is the game flawed?

Not sure if this is the case, but that happens often to me at the end of the quarter or if I start with a forward or center.