When using Save As with greyscale images, the image profile seems to be deleted from the new image. According to PM info, the profile is still there, but when opening the image in Photoshop, I get the following error: "The embedded ICC profile cannot be used because the ICC profile is invalid. Ignoring the profile." I use Grey Gamma 2.2, but other greyscale profiles behave the same way.
This is not intermittent, it happens every time (at least for me).