It got away from him because of the touch from Krul. If he rounds him with no interference at all he's getting to that ball and putting it away.
I agree he takes a step to see if he can get to it, realises he can't and goes down. It should be a penalty even if he stays on his feet, but we all...
If "keeper spreads himself at feet of attacker one on one with him, misses ball but catches striker causing him to stumble and fall" isn't a penalty, then our game has changed immeasurably and this decision is really nothing to do with VAR at all.
Just why? Maupay rounds Krul, Krul doesn't touch the ball and their feet clearly make contact. Maupay doesn't stick his foot out or change its direction, he tries to stay on his feet for a stride before going down. I really don't understand this one.