Typically PAL broadcasts from a film source use 2:2 pulldown. That is, all frames are duplicated (to make 48 fields), interlaced (into 24 interlaced frames) and sped up to 25 frames a second. As a result this pretty much translates to 25 unique frames a second. If you ever notice interlace artifacts it's usually because someone edited it badly and the fields are out of sync. That can still be corrected because there are no duplicate frames as in NTSC and they can be shift back where they belong.
Now for whatever reason THIS movie consists of a pattern where:
So every other field is a blurry merge of 2 film frames and every final frame is an interlaced combination of one good field and one merged field. This pattern shifts during the movie.
This is could be the result of a bad telecine process(?)
I could suss out where the patterns shifts and throw out the blurry fields, but that would result in a half resolution movie being resized to full screen.
Since there are already compression artifacts, our old laserdiscs caps would probably look better by the end of that.
Option 2 is to slow this down and keep all the crap as it is and make a 23.976 fps 100% interlaced video and apply 23.976 to 29.97 pulldown flags.
That could get ugly on playback since your player would be interlacing interlaced frames.
Option 3 involves duplicating frames to make 29.97 frames. And this would result in jerky video.
I'm not sure there is a good answer to this.