Missing portal from mission

Since pogo started, a lot of portals removed. Some of them was part of mission(s). The big problem is, that some of these missions is part of a big banner.

Let's say, there are a really big banner, for example with 60 missions.

I started it, and when I finished with the 49th, in the 50th, there is a non existent portal. What now?

So my question is, what happens, if there is a removed portal from a mission. Can I complete that mission, or I just messed up my profile page?

It could be playable even if there is a deleted portal:

If a portal is missing (deleted maybe?) and a mission uses it, what happens to a mission?

In this reddit post, somebody mentioned that if the number of portals are less than the minimum required number of portals for a mission then the mission will be deleted automatically.

This last information is not confirmed. I heard rumors that if all the portals were removed from a mission and you start it, you did immediately finish it.

If the mission still exists, it should be playable and appear in your profile as normal. (Unless the author has been an evil SOB and requires details rom a mow-deleted portal in a subsequent question. Fortunately most mission authors are nicer than that.)