I think the biggest issue United have had so far in breaking Astana down is that their front 3 are staying too far forward. Often times in possession you have Gomes, Greenwood and Rashford lined up on the edge of the 18 yard box and all the movement is horizontal. They're not backing off and trying to run in behind with momentum and there's no one making overlapping runs on them. That legs Astana's defenders basically just line up on the edge of their box and stay tight.
There's been decent options with Dalot out wide, but for all the talent the youngsters have, none are big arial presences so when he gets the ball it's either a cross into the box that's easily dealt with, or cycling the ball back to Fred or Matic in midfield to try again.
I'd love to see Rashford of Greenwood back off a bit and get a running start at a ball that's lofted to about 10 yards out. Even if you just make that movement you force the defenders to either risk the ball over the top move with you and force a chance in line shape.