Someone turned on the date stamp before taking several hundred photos. I created a JPG mask and exported it, then selected all of the landscape-oriented photos and imported the mask (from file, replacement, selected cameras) with no problem. But when I did the same thing for portrait-oriented photos, about half of the masks ended up in the upper-left corner instead of the lower-right. Windows and the PhotoScan Photos pane agree which way is "up" in those photos, so I'm not sure why this happened. I think the orientation came from the Canon camera, if that makes a difference.
This is a very minor bug. Version 1.2.6-2834, on Windows 10.
Thanks!