Although this was on ps4, it may help
I know many of you are experiencing the same issue as I did: The tides of war look up challenge does not trigger, even after multiple v1 multi kills.
Think I've found the solution.
The quests paths are broken, meaning if you have a quest open prior to the look up, the look up challenge will not trigger. Doesn't matter how often you try.
For me this was the "spot 15 enemies", which should be optional. After completing all other tasks of this week, the v1 kills did trigger the quest and I got it the first go after clearing all prev tasks.
So, try clearing all other challenges of the second week and try again.
Hope this helps you as well.
Good luck!
