I've rebacked Astana +0.5 after a drift today. Drift makes zero sense to me personally. Been thinking about it more today as well. Couple of decent games that sort of help with a comparison. Obviously its hard to say exactly what the correct line should be or exactly how the game will play out so can only take a calculated guess.
I was on United u19s -0.5 away to Young Boys last year in the UYL. It was not a great bet, I massively underestimated the difference that the artificial turf would make. The astro at YB is much better than the one in Astana. Think 5/6 of the expected starting XI played that game. Gomes, Greenwood and Chong all struggled on it. Garner dealt with it okay though. I can't envisage any way that +0.5 will be a bad bet unless Astana think they'll win 6-0 easily and try to coast it. I've got Astana odds on, really surprised they haven't dropped further still.
Another decent comparison was Doncaster v United u21s in EFL. Doncaster played their reserves, was 3 first teamers. They kicked off around 1.8 and traded 1.5 after 15 minutes. United sneaked a 2-1 win late but were fortunate. Laird, Mengi, Galbraith, Chong, Greenwood all played that game. Astana are much better than the Doncaster side that was put out that day, even without factoring in the weather, pitch and travel as well as the home crowd. United will of course be stronger also but not as much as the step up from Doncaster > Astana.