I have a an 08 4runner with the 4.7. I also had the same issue. I did some experimentation, after being told by the dealer and that's the way the transmission was programmed.
Here's what I found: I would back out of the driveway and shift into drive before the vehicle had come to a complete stop. I'm talking about a foot a second. The wheel sensors were reading a reverse rotation of the wheels and delaying the the shift into drive. ( They're very sensitive. If you've ever stepped on the brakes a little to quickly, you know how little pedal pressure it can take to activate the ABS.) Sensors are extremely sensitive to wheel rotation. With that said it does take a bit, 1-3 seconds, for the electronics to perform the shift.
Try coming to full and complete stop, before the shift into drive and see if that helps. This is the first fully electronic controlled transmission I've owned. Took some getting used to. The older hydraulic valve body transmissions were much more forgiving. When you moved the lever, the transmission shifted.
Hope this helps.