XMP sidecar name is wrong
XMP sidecar name include the extension of the camera file. It should not.
img_8211.jpg should have an XMP sidecar img_8211.xmp and not img_8211.jpg.xmp
#2 Updated by hfiguiere - over 8 years ago
XMP Specification part 3, section 1:
"For applications that need to find external XMP files, look in the same directory for a file with the same name as the main document but with an .xmp extension. (This is called a sidecar XMP file.)"
See bug #265 for the interoperability problem.