I have seen this several times, in Superstar Mode (it probably also happens in other modes too). When I'm the QB and I pass to a player, and he runs forward, there are times when he gets pushed backwards and the system shows that I lost yards! Scenario:
Line of Scrimmage is the 10 Yard Line on my team's side of the field. I throw a quick pass to a receiver and he runs forward to the 15 yard line. He's met by the opposing team and pushed backwards to the 5 yard line. The call is that I lost 5 yards and the line of scrimmage gets moved back to the 5 yard line.
In real-life the ball would be marked at the 15 yard line and ruled "forward progress". You can't force a player backwards and make him lose yards!
What's happening, in the game, to cause this bug, is the NPC receiver that catches the ball...it shows him doing the run animation; as if he's running away from the people trying to tackle him. However, he's fully covered on all sides, and the opposing team is pushing him backwards. The game engine thinks he's moving under his own power which is why it's not ruling forward progress. However, that doesn't make sense. No player in real-life, when he's surrounded by 6 people trying to tackle him, that are pressed up against him, is going to turn around and run straight backwards. That would be illogical. And even if his feet and legs were moving, because the other team is making contact with him and pushing him, it would still be ruled as forward progress.
That is how real-life would work. I know, in the game engine, it doesn't think it's forward progress because the receiver is doing the run animation, and the game engine just isn't paying attention to the logic of how real-life players would handle that, and how real-life referees would call it. So it's a game engine logic problem. When it's 1st and 10, and I throw to a receiver and he catches and makes it to the first down, but then the opposing team pushes him backwards 12 whole yards, and then I get a 2nd and 12...that's ridiculous. It wouldn't happen like that in a real live NFL game.