Same here, there are more posts with this problem from around 18 november. Hopefully there will be a solution for this. If you search on the word pledge you'll find the other posts.

Same problem here. Hope that there will be a solution or fix the coming days because it's already 18 days after this post started. When do we can expect to hear something?

Same here. 16 days and counting..

@andrewmemorex same problem here. I can only go to level 160 regions, but can't finish te questline. Ubisoft fix this problem!

I am finished with the full Grantebridgesire storyline. So I continued pledging my allegiance to the other regions and finished their quests. Now I'm on the point that I can only pledge my alliance to level 160 area's, probably because I have the issue that my Grantebridgesire area(quest) isn't completed. What is a 'permanent' solution for this problem?