TotE - Father Sky's Fury

[aquasquirrel]

I apologize if this has been discussed before. I'm hoping there is an answer.

I'm playing the mission on "Hard" Difficulty. I've destroyed all the castles except Cogston (southeast corner) . I cannot enter Cogston and all the Red heroes retreat when I engage them. I need to defeat all enemies to win the mission. I don't know what to do next.
Is this a bug?

[aquasquirrel]

Nevermind. Restarted the scenario from the beginning and it behaved normally this time. I haven't had that happen to me before..... Weird.