Confused about how operations work

I keep getting my progress on operations reset. I jump into someone's game, do one of the missions in an operations, then jump into someone else's game and do another mission in the same operations but my progress is still only 1/2.

Does the operation reset if you go to a different host? If so, that's really dumb. What if the host disconnects in the middle of a campaign?

Why doesn't it just count consecutive missions in the same operation area as progress towards an operation? Regardless if I host one, Person A hosts another, and then Person B hosts a third....if I do 2 missions in a row in the same operational area, it should count both of them as progress to the same operation.

It almost seems like the only way to ensure consistent operation progress is to host your own campaign.....which is dumb. I don't have friends that play, and no one is joining my SOS.

Am I missing something?