What size paper is this intended for?
Appears to be A4 (Metric Standard, 210mm x 297mm).
You can print them on Letter size, 8.5in. x 11in., if your printing dialog offers a "Fit To Paper" or scaling option.
That's what it looks like based on setting printing to A4, but even though I set to Actual Size, my result seems like it printed too small in a way that makes it so the lines are not at the even 1/3 folds.
Just an educated guess, but perhaps printing margins has to be turned off?
