Foster had 3 deep balls thrown his direction.
1st deep ball caught but thrown out of bounds.
2nd deep ball Foster got caught ball watching. He ran with his head starting at the pass instead of putting your head down running and looking back for the ball when it gets to you. Ball should have been caught if he tracked it properly but because he wasn't running at full speed and ball watching it fell out of his reach.
3rd deep ball Allen was scrambling and Foster stopped running cause he thought that Allen wasn't going to throw his direction. Would have been an easy TD if Foster didn't stop running. When a player has an arm like Allen you have to be prepared at all times.... He gave up on a play and it should have been a TD.
And I haven't even mentioned his drop.