Hi Kirk,
thanx for your quick response - It's only that one particular folder with that strange behavior, I've a lot of other images without any issues...
In the meantime I've changed one setting: "Read embedded XMP before IPTC" is now selected and active. Without this change (before: "Read embedded IPTC before XMP") I was not able to crop any image :-(
But this doesn't fix my "orientation issue" here.
Since it's a NEF, I cannot attach it here (too large), please see: [edit: removed after downloading]