Canon i550 tries to print as an 8x10 on 4x6 paper

Occasionally, the printer tries to print as an 8x10 even though I've
loaded it with 4x6 paper. So what comes out is only the lower left
quarter of a Landscape (or Portrait) image. There is no attempt to print
the remaining three quarters on three more sheets of paper.

Using Start/Settings/Printers/Properties, I've selected:
Page Size - 4 x 6
Orientation - Landscape
Borderless printing - On
Glossy Photo Paper
Print Quality - Standard or High
Color Adjustment - Manual (all slider at factory defaults)
Preview before printing - On

I'm using Irfan as the application. I've used it many times, and the
vast majority of the times it works properly.

In Irfan, when I click on Print I go to a Print Preview dialog box. I
select Center Image and either Stretch to Page or Best Fit. (If at this
point I select Change Printer and look at the i550 profiles, they are
exactly as listed above.) Once I click on Print and go to the Preview
mode, the image looks like a complete, normal fit to the paper size.

Thanks in advance.

Ray