Replying to old post in case someone searches looking for a solution.
The system is "purging" the yellow sheet because you only have 1 page in your document and the NCR paper is defined as an "ordered stock" with 2 sheets to a "set". To properly print on this kind of media you need to have as many pages in the document are there are sheets to a "set". In this case, you would need a 2 page document. In this instance, both pages of the document would be identical.
Another way to resolve the issue would be to remove the "ordered stock" parameter on the NCR stock. However, this is not recommended as the machine will not properly purge sheets after a jam to reset the order of the stock.
