Brake Booster Hose Question on an Inline 6

[brap999]

I'm replacing all the hoses under the hood, and while doing so I realized the previous owner who installed the brake booster installed the hoses in a way I haven't seen before

I searched the forums to see how others installed it, and it seems everyone just runs a hose from the intake straight to the brake booster.

However, in the photo attached, you can see the previous owner ran a hose from the intake, to a T fitting, where it splits off into the valve cover, and the the brake booster.

Would this cause a vacuum leak? I'm a little confused here.

The brakes do work great, so it doesn't seem to effect my ability to stop. However I have a hesitation/stumble I've been trying to track down when I hit the throttle hard. I'm wondering if this could be the cause.

I never thought twice about this setup or even noticed it until today.