The difficulty is intentional. We've tried to account for player theory crafters who generally do a great job of finding very powerful strategies in these pieces of content.
From the Q&A.
How exactly are we supposed to come up with those strategies when don't even know what enemies we will be facing in the normal combat missions because they are random?
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They said that the difficulty is working as intended. They cancelled it because of bugs that were occurring revolving around what zones opened up in phase 2 and which ones didn't.
I think the "glitch" is a convenient excuse to cancel the event, tweak the difficulty back 5% and rerun the event in January. When it's a little easier, just claim it's the increased rosters.