Custom sized print job only printing part of image?

I am trying to print an oversized print on my Epson P800.

The custom paper I have created is 17x21, I am using a piece cut from a roll.

My print appears normal all through the printer settings and adjustments. Margins, cell sizes, etc. But when I print it is only printing the top half, exactly half on the vertical and the full horizontal. 

I thought it it had to do with the "Paper Handling" area of the "Print Settings"? 

Teh "Scale to fit Paper Size" was off, but when I toggled it on the resulting print was even smaller, 2/1/2" inches vertical and full width, cropped.

I have had issue with custom paper sized my whole life in Adobre products. It has been awhile since attemptoing one, but before this gets absurdly expensive I hope to find a solution.

Thanks