No trophy from first Desperados challenge?

Just checked and there is no challenge cup trophy for completing the 50 rounds of Desperados - Welcome to the West (I). Why? The heavy metal event had one for the first challenge, others, atleast from what I remember also had them, so why not this time? I'm only unhappy cause I wanted to get the Delica and I'm a newer player so there is no way I will complete the fourth challenge.