Absolutely needs to be addressed. I just ran into this issue myself.
If the unlock requirements really need you to have not upgraded, it's too missable on Path of the Damned, as you're obviously GOING to upgrade to aid survivability. I'd already done all the other available side content before starting An Untimely End. Probably way over-levelled for what it's expecting, but that's how I play RPGs; side content first, main story later.
Easiest "fix" in my mind would be to have this quest not count towards the all sidequests achievement, or have a safety trigger when An Untimely End is marked as complete.