My settings below Application Preferences:
Dimension Settings
Drawing Unit: Inch
Paper Unit: Inch
Measurement System: Imperial

Printing - Page
Page Orientation: Landscape
Paper size: ANSI A (Letter)
Paper width: 8.5"
Paper height: 11"

Printing Colors
Color Mode: Black / white

Blank QCAD template used as the start drawing.

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Issue in Layout Block

Printing Color Black/White changed to "Full Color Mode",
Default setting to use ANSI A will change to ISO A4 in mm regardless that the Paper Unit is inch and size ANSI A.
Unit is unstable when you change the format a few times. It will switch between mm and inch what can lead to a 8.5 mm x 11 mm Paper size (then called customized!) or 210" x 297" ANSI A4,

Paper orientation preset to Landscape is then Portrait in Layout Block