Not sure of the dryer you are using, but I would try doing the following:
Apply a very heavy amount of spray (around 85-100%, or possibly more)
Reduce the dry time and temp to lower heat (about 285 F) and longer dry time (up to 14-16 minutes)
I found that the Kornit ink does not seem to dry at temperatures below 270 F, so you do not want to go too low. The idea is to just slowly pull the moisture out of the garment, so the ink cures and dries properly.
One other thing you could try, is adding a delay between each layer of ink. I found that about 30 seconds between layers works pretty well. I know it is not ideal, especially when it comes to the times you have to wait, but these types of garments are not very good, when it comes to waterbase ink. The fabric was made to repel water, so it tends to repel waterbase ink as well.