If the defender has made a deliberate action to play the ball and makes contact it then he’d be playing everyone on side. However in that case because of Armstrong also being in an offside position it could still be given as offside as he also tried to play the ball and influenced JPVHs...
Alexis Mac Allister had a wonder strike disallowed against Leicester because Enoch Mwepu was in an offside position when a free kick was taken and he attempted to play the ball, so we've been caught out by the same rule.