Sounds like a layering problem. Next time it is saturated by rain, if it does not work up well after that it is not going to OK without more work. The best results I have had with any kind of amendment is to till most of it - 3/4 ish - into the top 3 inches if you can even get that deep. Establish your grade and compact that much (I realize you may be beyond this point now), then add the rest of your amendment material and mix lightly into the top 1/2 inch.
I have not used the Marmix brand. We do not typically use brick dust in this part of the country either so I don't know how much help I can be. I have had several good e-mail exchanges with the guy at this
site. He knows what he is doing and is closer to your part of the country. He may have a better handle on what you are starting with there. Looks like he is about 80-85 miles from you.
Good luck. Chances are if you keep working it in and get it compacted it will be OK.