I too am experiencing rating transfers between PM 4.6 and Bridge.
Both on Mac Leopard and Windows XP64
I'm working with Tif and dng originating from a Nikon D3
PM Prefs:
Files = Add tag, color class and rating to IPTC/XMP (For all photos)
x Add IPTC-NAA Resources when embedding IPTC
For JPEG, TIFF, PSD, DNG photos:
(Add both embedded and IPTC4XMP)
Am I missing something or should I wait for an update?
Jb.