I have a 126 page PDF that I imposed to repeat 2-up on 11x17. Most of the pages are being printed on 11x17 "Thin paper" while ~8 separator pages are being printed on "2-sided coated 4"

I can click on the "Default Media" link beneath the sheets I want to specify as 2-sided coated 4 for all but 2 of them. The 2 that I can't come up with the error you see above.

How do I fix this?