Yeah, it's a thing I've noticed as well. Especially for DT/MLB they come up the A Gap. They will be heading right for the QB, and without the QB 'flushing' they will 'anticipate' him bailing and try to cut him off.
Just for the QB to not move at all and deliver the ball.
I mean, I still get like 9 Sacks a game so I guess losing some of them doesn't hurt... I'd just rather lose them to a Stiff Arm or some Evasion instead of my guy stopping mid-Sack to run to the Hot Dog Vendor.
:D