Mike,
You have embedded XMP data in your image. It has an unusual xml:Label in it:
xmp:Label="+3*, 4*, 5* = A Edit / Website Stock"
I'd venture a guess that you don't have a color class in PM with the same name as that.
The XMP data has a xmp:Rating of 4:
xmp:Rating="4"
The XMP data has a photomechanic:Prefs value:
photomechanic:Prefs="0:1:0:002145"
Rating=0, Color Class=1, Tag=0, Frame=2145
When I step through the code in PM it comes up with a Rating of 4 and a Color Class of 1. I have my PM5 IPTC/XMP settings set to Read embedded XMP before IPTC for JPEG, TIFF, PSD, and DNG photos.
I think if you adjust your settings, you should see the same results I get. For the future, you should make sure that your Color Class label names match in all applications that you use together (I don't know if you already do that.)
HTH,
-Kirk