The second link is what I am referring to, which is a couple clicks into the thread referenced in Manfred/MJS7643's reply #3, above.
It seems what is different in LR 4.4 compared to a month ago when it was merely a warning in PS that was seen, is that LR 4.4 now actually respects the bad 1.8 gamma of the PM-embedded profile instead of ignoring it as it had in previous versions.
The issue that is still not understood is why a LR 4.4 RC on a VM is choking on the files that have had the ProPhotoRGB corrected to have a gamma of 1.0. This is, perhaps, unlrelated to LR 4.4 making things dark as the embedded profile tells it to.