Portrait orientation not working for Paper Format > Letter

In a new text document created in LibreOffice the document prints as landscape even though the Paper Format > Orientation is set to Portrait. This only happens when Paper Format > Format is set to Letter. I checked formats A4, A3, Legal, and Long Bond in both Portrait and Landscape orientations; they all work correctly. Only Letter shows up as Landscape even when Orientation is set to Portrait. To save time and paper I am judging this by the page appearance in print preview. The results are the same with print preview, printing to a PDF, or printing on actual paper.

Is this perhaps related to the issue described by nobodhi in “portrait -vs- landscape are working, but in reverse”?

You didn’t tell, but you surely are working on a Mac wih OSX (Sierra?).