4 x 6 prints have unwanted border

In Lightroom Classic v 13.1, when printing a 4x6 photo there is a small white border on the right side and the bottom or top of the print. 

 I choose 4x6 Borderless Print, I make sure the margins are set to 0 for every side, I make sure the cell size in set to 4x6, I use 4 x 6 paper (Ilford Smooth Pearl) and I am printing on a Canon Pixma Pro 100.   I can print other sizes such as 5x7, 8x10 without any unwanted border. 

I can print 4 x 6 from Preview and from "Photos" successfully... no unwanted border.

I prefer to print from LRC but this prevents me from getting the prints I want.

See examples

Mac Ventura OS 13.6.3