I hear what you are saying readingfan, but I don't think there is any doubt that this is a case of mistaken identity. Seeing the way Mike Dean performs, I am sure that if (for example) he had cautioned Dunk for dissent or a subsequent foul, he would have made it plain to the crowd, the 4O, the managers.... and in all probability, the FA or PL or PGMOL would have confirmed this after the match. It is not being told that makes me think the FA realise there is a problem in this case. And, although I need perhaps to be careful how I word this, I suggest that a look at pics of Dunk and Bissouma will confirm that the hand which shoved the Arsenal player in the back leading to the first caution was definitely not Dunk's. This needs to be looked at by the FA pdq. I will say no more.
Arsenal player? It's mistaken identity all round!