Almost. I'd consider it more of a side effect of how the system is designed.
When you shut the key off, it takes a second or two for the *oil* pressure in the engine to drop below 5 psi, which is when the fuel pump shuts off. With cold oil/cold engine, it takes a bit longer to bleed down.
If you install a mechanical oil pressure gauge, it's really obvious as you watch the needle drop.
