I see similar bizarre rotation issues with MC. If I have a picture in the library that should be "auto-rotated" to Portrait mode (because of the way I was holding the camera), MC will often incorrectly display these in landscape mode.
However, if I select them, and hit "Rotate Left" or "Rotate Right" (depending on which way I need to flip them), they'll jump 180 deg instead of only 90 deg (flipping the image to the other direction of Landscape view). Then, I need to go one step back the opposite direction to get them to display properly.
Some pictures to illustrate my point:
First, an image that MC detected "wrong" and is incorrectly rotated.
I selected that image, clicked Rotate Left, and this is the result (a 180 deg change instead of the proper 90 deg change).
Finally, I clicked Rotate Right to get it fixed back the way it should have been.
It seems like MCs detection engine has improved, and it doesn't make the initial mistake as often anymore, but when it does (or when it already has with older pictures) this process is confusing. Also, I should note, this has been true for a
long, long time. I've posted about it before but never got much traction. Glad someone else noted it.