I have the same issue with the quest Defensive Measures during the Survive the attack objective. It's possible to [painstakingly] manage to get back to the "bubble" from the fast travel point in Asgard by choosing the option Reload Latest Save, dying repeatedly, and then saving your rations & adrenaline bars to utilize them with the Blinding Rush ability once close enough to the bubble (where the Jotun are actively attacking Eivor, which makes manually saving the game no longer possible since you're in combat).

However, once I make it to the bubble, I have the same issue as when I originally attempted the quest objective at a lower power level, where I survive the Jotun attack but the enemies either (1) stop spawning or (2) spawn but stay/patrol far outside the bubble.

While I still cannot trigger the quest Defensive Measures "Survive the attack" objective to complete, I can get Eivor to no longer receive any damage while outside the bubble in Asgard, allowing me to complete wealth and mystery nodes throughout Asgard. How to 100% "survive the attack":

1. After defeating all enemies that you can once back within the bubble, save the game.
2. Go into settings, then download & switch to any other voiceover language pack (for ex, I switched over to French from English). The game will reload once the changes are applied. 
3. Quickly press start and fast travel somewhere within Asgard. 
4. Enjoy "surviving" outside the bubble!

Videos on the bugs/glitches and how to out-glitch them:

• (upload still processing as of 11/25)

Hope this gets fixed soon! In the meantime, at least this method gives us a way to complete any side nodes in Asgard while the bug is being worked on.

All the best

If you're like me and went back to England and no longer have a viable save to retry, here's a link to my post on how to at least be able to get Eivor back to the bubble then how to no longer receive damage while exploring Asgard: https://discussions.ubisoft.com/topic/79956/quest-defensive-measures-bug?lang=en-US

• Part I
• Part II
  (upload seems to be stuck processing but directions are in the video description and on the other Ubisoft forum post)

@fuzies777 Thank you for sharing this fix. Unfortunately, I've previously turned in all the bureau codex pages before Reda decided to not want to interact with me anymore

My gameplay (PS5) showing that Eivor can interact with Thousand Eyes NPCs in other towns but cannot interact with Reda within player settlement:

I'm also unable to complete the Defensive Measures quest in Asgard. I can get it to where I no longer take any damage inside (or outside!) of the bubble but no matter how many goons I kill, the quest does not proceed:

I have been attempting to complete the Defensive Measures for months now with no luck. When might this issue be resolved? Below are links to gameplay of my attempts to complete the quest in the current version of AC Valhalla (v1.2.0).

Thank You