Every single AFB ever made bogs to some degree. If somebody says they have an AFB that doesn't bog at all, they are either lying or they cannot feel it and don't know what to look for.
The AFB is designed to bog. The secondary air door is positioned under the boosters. As such, there will always be a delay in the time it takes for the booster to see the air signal from the secondaries opening.
The AVS on the other hand was created to solve this very problem. The air door was mover on top of the boosters. In this way, the boosters see a signal as soon as the secondary throttle plates are open.
You will be able to tune the secondary bog out of an AFB only so much.