Abadionick

Well my friends and I were going. To have free for all and then when we went to start it changed to Spartan ops and it is a new Spartan ops mission I never played and when we finished it it said it was episode 4 mission 4 on i think. The name sarce or something like that it involved jul madam and a gift from the didact it was the core mission in reverse. I wanted to report this glitch because it seemed so random and I wanted to know if anyone else had the same problem.