Patrol mission can't be completed?

[lunario]

Hello.
This is my first post here.
I finally installed SH5 with TWOS properly and that's awsome.

But I'm having some problem completing mission objectives now.
On my second patrol I choose the eastern waters and I finished three secondary missions. Each one I'll receive a encrypted radio message to tell me where to patrol and the radius and time.

However on my third and now fourth patrol. I didn't receive any radio message about that. I completed my first objective on my third patrol and the new objective icon appeared, with no radio message to let me know what it is.

And on my fourth patrol I reached the patrol area and patrolled for more than 3 days, still can't finish it.

I don't know what's wrong. My third and fourth patrol are northwest waters, maybe that matters?

PS, How do I know how long should I stay in the patrol area to complete the objective(if I can't receive the encrypted radio message to let me know that)?