Why are my through pass receivers making weird runs?

Here (https://imgur.com/a/95PyKBD) is the video shows three through pass clips in a single squad battle (Team of the Week Team, semi-pro).

In the first two clips, after the through balls were sent, the receiver Grealish didn't make full speed runs until much later. And he was just jogging while looking back. Is he mimicking Usain Bolt???

In the third clip, the receiver Lewy changed the sprinting direction in the middle and lost the best timing to get the ball.

Is this my mistake or how the AI is supposed to work?