After attacking Tamworth I leave to meet with Sigurd and the Ragnarssons but when I get to the Tame river the triangle barrier appears and the "area not available" message shows up. If I fast travel across the river it kills me and I get sent back to the end of the attack on Tamworth. I also can't manually save and autosave is not working either, so I keep having to do the start of the Bartering mission again and this has happened four times already.

And a much smaller bug that's not game breaking, when I was customizing my Jomsviking, there were three Raider's Axe options when I had only enhanced it once. Two had a picture and worked fine, but the third one was blank and when selected put a model that looked like a mannequin with a transparent red outline in his hand. It only appeared in the customization page, when I equipped it on him and left the menu to go to my ship and see if the mannequin was on him, the Raider's Axe was on him, not the mannequin. But when I back to the customization menu the mannequin was still there.