It switches, from repeating every 4th frame, to normal pulldown (3 frames, 2 interlaced). And it often does so over fairly short sequences.
There's always enough movement, that pulldown should always be noticable.
I haven't worked out any sort of pattern, to the switchover, but that's partly because it gives me a headache. :) Weird...
What if the IVTC was set to decode the pulldown sections to extra frames? If that made the repeated frames consistant...
Edit: Wait a minute... I loaded an mpg into VideoDubMod, (which ignores the flags, right?) And now I'm seeing an irregular pattern of pulldown, but I don't notice repeated frames.
GSpot says the mpv is 23.976 pics/sec, and 29.970 frames per second.
So, if the duplicated frames are rid of, then IVTC probably would make it run faster?