He is running in line with akanji towards the ball, obstructing his view and actually meaning he would need to go round. Look at the space between the ball and bruno, if rashford is not there the ball is dealt with by either keeper or defender comfortably. There is no way to sugarcoat this one, if the VAR has the bollocks to correct the ref then it's given offside.
Calls for the ref to go have another look at it are, imo, off as well. Just tell the daft **** he got it wrong, call offside and carry on from a free kick - easy.