Canon LiDE 400 scans have seams at high resolution

When scanning images on my LiDE 400 at higher resolutions (1200 or above, possibly also visible at 600 if you stare hard enough) the images appear to have vertical seams where a few columns are missing from the final image. I have not been able to reproduce on Windows using ScanGear, but the image quality is worse (the image has color fringing, presumably from the scan head moving too quickly). I've attached a very small region of a scanned image where there's a visible seam in a halftoned print.

I'm currently using sane 1.3.1 and xsane 0.999 for the frontend.

Please let me know any additional information I should attach.