I have ripped my blu rays as mkv and sometimes even though they are correcctly tagged "23"Hz ie 23.978, MC selects 50Hz. I have set up Options/Video so that 23p content triggers the switch to the correct frame rate.
It seems temperamental problem in that some blu rays trigger the frame rate switch while others don't.
I have TMT 5 and 6 and Anydvd, all with frame rate switching disabled to rule that out, though unlikely.
Any ideas why frame rate switching may be temperamental?