Step by step:
FIRST
If I take your footage and drop it in AE it tells me it’s 25 FPS with fields
TRUE or FALSE?
Then if put the 25 FPS footage in a 50 FPS comp to see, and advance frame by frame you will see there is something wrong with the second field – right, it does not move, it’s just blurry?
If I in Interp Footage say there is no fields, then see as you play frame by frame that there are some field artefacts
Is this the sample you sent me that is like that or your actual source footage is like that?
Pierre