This comparison isn't too helpful because the subject matter isn't the same and neither part of the print looks very sharp as presented here. If you were to do one print upside down relative to the other (rotate the image 180 degrees and print it), then one can compare the same subject matter as it comes out opposite ends of the paper. Also, it would help to chose a really sharp photograph just about from edge to edge for analyzing whether there really is a problem.
What paper were you using which displays this problem? How did you load it in the printer (Front Fine Art Feed, or Sheet Feeder)? What Media Type did you select in the printer driver? These factors at least can affect how the printer handles the paper, which could have an impact on the results. The fact that Canson BP doesn't present this issue indicates it may be more a problem of settings and how you are feeding the printer, rather than the printer itself.