Yes, Bob. Your camera has a micro-contrast detection device. If it detects high micro-contrast, it looks for Zeiss lenses. If it detects lower micro-contrast, it looks for a reference of the right focal length in the Canon stable. The only f:2.8 Canon lens that can have a focal length of 21mm is the 16-35 IIL.
Now the question is: why do your shots exhibit less micro-contrast than the typical Zeiss shots? The answer to that is that, for those Dachau shots, you used even more vignetting than you usually do, and that is "seen" by your camera as reduced micro-contrast.
try a few shots without vignetting, and you will get the right EXIF IMHO