Host migration swapped missions?

[(PSN)Maliades]

Okay so a little while ago I went into a spy mission - an alert. after a few minutes in the mission I got a host migration - no big deal, I thought, happens all the time. The reloading screen pops up as it usually does and I find myself in a completely different area to where I'd left. But then I realized, not only had I been displaced physically, but I was in an entirely different mission than what I'd just left. It had put me in a defense mission three rounds in.

Correct me if I'm wrong but I don't think a host migration is supposed to take me out of a mission entirely and put me in a different one. And I know it wasn't an issue of missions being done because the spy mission had just started, even then I figure it would have dropped me back in my ship rather than slap me in a totally different mission and area than before.