Can you tell me which pages you see this problem in?
I was very careful over this, and atempted to choose a very low inpack background for that reason, I don't see this problem myself, but I want to correct it if its causing readability issues.
What are you using to open the pdf? I have had multiple people inspect it, did it myself in multiple PDF readers, and I have never seen it look like that. The pdf should look like it does on the example pictures to the right.
