Have you tried turning off borderless? That’s how I'd find out.
On an Epson it seems the borderless setting slightly expands the image - even if it already fits.
Canon may do that too. You'd need to contact them
Edge to edge printing can be hard to achieve.
I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer:: co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management