Went for a ride today with the new setup. I purposely filled the hydration up, almost to the top. No bueno. I need to double check but I think the fill cap is only a single baffle design, which is probably the reason why. Water squirts out of the top continuously, sometimes 4 inches high. Once the water lowered though, it was a lot better. A side note too, is that I was riding pretty harsh roads. So we just have to fill it about 1/2 to 3/4 full.
The bottle also came with a "no fill" plug. I believe if you use that, you won't have a problem with leakage; but then you can not fill on-the-go. I did test this and filled the front hydration with my water bottle. It worked great. You can now pull your bottle out and the fill cap stays in place. Overall, I believe the new design is much better. I'm going to see if I can help with the squirting water somehow.