Half sat half laying on the ground? He runs our shifting weight from foot to foot ready to dive either way, and as soon as he is close to the attacker, the boro player pulls it back, as that ball is played Stockdale dives. He had no chance to grab the ball.
He absolutely made a very basic mistake for the second, but he can't be blamed in any way for the first.
The first was a collective cock up. He's hesitant but not the worst offender by far. The second is down to him, simple as.