To answer your questions,
- We don’t know what X is. It appears to be random. The faster and more often you get maps outside of your rotation, the fewer games it takes. It’s not a set number, as it depends on luck of the draw (apparently)
- Are you in the fourth “category” Co-op vs AI solo, and over the course of many games in that “category” still falling into the same 4 maps, following the same or similar order?