I have a clip which is 720p30 and plays back perfectly smoothly when opened outside of premiere. When I import the clip into premiere and play it back it looks awful: https://i.stack.imgur.com/V0NZR.jpg
If I export the sequence it looks the same as in the preview (interlaced and awful).
Premiere indicates that the clip is 1280x720 (1.0) which is correct and the sequence preset I am using is AVCHD 720p30. I have tried fiddling with interlacing settings (though none should be necessary) to no avail.
I have a project full of different 720p clips from different sources and this is the only one that is exhibiting this behavior. The problem clip was generated by another program.
Any idea what I'm doing wrong?