Rewatch the sequence (the second replay).
Lindelof was not giving chase until passer released the pass. He kept his eyes on the passer the whole time and held the halfline (offside trap) which is sensible thing to do.
Edit: read your post wrong. My apology.
Yes,Maguire being slow is one thing. Some slow CBs in teams playing high line: Pique Hummels Blind Sule aged Boateng to name a few and they are not as much an issue as Maguire. The main issue with Maguire is that his first instinct is backpedalling, when it should be reading the situation, and being aware of where he is, then act accordingly. This happens all over the years, even in his great form. It's just getting more exposed the more we try to implement a high line.