This happens when you create an infinite loop in your graph. E.g, in a single update, State 1 goes to State 2 which goes back to State 1.
The usual fix is to use the Next Frame Event on State 2 to return to State 1. This says: "I'm done for this frame, but in the next frame return to State 1." Then the loop repeats in the next update...
Otherwise Playmaker keeps looping in a single update and you hit the loop limit. This limit prevents Unity from hanging/crashing which is what usually happens when you code an infinite loop!
Does that help?