Yes, jmone, I accept the limitation that the frame rate is set upon playback. As it's been explained, once MC has launched the BD menu, that effectively becomes the player. Unlike a standalone player, it cannot change display rate. If I use the menu to navigate, and the display is 23p, it will play non-film video at 23p. Instead, I would do title playback. MC prompts for Blu Ray menu or title playback, and I choose title.
There might be a way to configure MC's display rate changes to do this (whether using JRVR or MadVR), but up to now I'm using profiles with allowable display modes in MadVR. So film could play at 23p (or 59p), non-film video at 59p (or 29p for that matter), PAL at 50p automatically. I think there was a way to depend on desktop settings only, but I've let MadVR deal with it for a long time.
With JRVR, there seems to be a disconnect between desktop settings, the display rate JRVR chooses, configuration for change mode, and the content. I'm hoping the issue is that I don't know how to configure it correctly. Film at 59p instead of 23p is not a show-stopper, but video at 23p kind of is.