TLDR - If siege isn't rewarding you properly it may be worth waiting a couple of days after the weekly reset to complete siege mode for the accolades.
I, like many other players on this subreddit, have had a hard time getting accolades for completing 15 waves of siege mode. I’ve been trying to trouble shoot the problem by running 15 waves with bots to eliminate host migrations or late start problems.
What I've found is that if I run siege the day the weekly reset happens, I have around a 25 percent chance of actually getting accolades. Whereas if I wait until Friday or later that goes up to 100 percent chance of getting the full siege rewards.
I thought this might be a problem related to