[Dave LaRonde] “Could there be a frame rate mismatch between the sequence and the footage?”
I agree with Dave. The juddering appears to be a frame rate mismatch between the source material and the sequence.
Your sequence is 25p. If you are editing in source material that is not 25p (i.e. 23.976 or 29.97), the result would look like the video you posted. If you are incorporating any footage that is not 25p in your 25p sequence, the mismatch in frame rate is responsible for the juddering.
Try changing your sequence settings to 50i instead of 25p. Premiere Pro will then attempt to add pulldown to any non-25p footage in order to better blend it with the 25p footage. If frame rate mismatch is your issue, then this should help.