I don't watch enough or certianly in detail man united games especially their attack, to definitively know whether that's the wingers' issues with that poor stat.
I know rashford has been criticised for his selfishness this season (amongst other things), but it seems like they don't work with each other on the training ground in attacking plays.
One thing Martial has always been complimented on over the years even from his harshest critics, has been his ability to link-up play, same goes for weghourst last season.
That poor stat therefore might easily be as much down to hojlund as it is attributed to Garnaucho and Antony. The #9 needs to make the right runs to be fed the ball too.