Probably just symptomatic of the type of player he is. He is frustrating by his very nature, so when things do not go in our favour he will be an easy scapegoat.... even though he is capable of popping up at just the right moment to make a difference.
Puncheon was very similar but with a far-far worse team ethic. Personally I am quite glad Guly had the chance to establish himself in a winning team otherwise I fear he could easily have been pushed out in the same way.