It looks like only Actions are restored. Not flags, nor JPG quality.
Additionally, if the actions are Brightness and Contrast then they are restored as two full Adjust (Brightness-Contrast-Gamma) actions. This is understandable as for import behaviour but looks quite weird.
I'm using XnView Classic for a long time. Today I gave a try to MP, primarily for its Curves tools and more powerful Adjust tool. And I must say MP seems to be very cool! (it was not intended to be rhymed :D )
One issue I've got for now is one with Batch convert presets (.xbs).