This is an obscure bug I've reported before, probably in MEP MX. (If I can find them, I'll post the old thread links.)
It's not easy to reproduce. Briefly, what hapened this time was as follows:
1. I imported a still image and used Section and Size/Position to edit it.
2. I later externally edited the image, saving it with the same name.
3. In MEP I deleted the original from the timeline and dragged in the revised one from its Explorer folder.
The preview monitor showed it to be distorted.
4. Placing it anywhere on the timeline, on any track, it remained distorted. Using Reset video effects made no difference.
5. I deleted it and changed its name in Explorer and reimported it to the timeline. It was then displayed correctly. That's the only fix I've found.
6. Changing it back to its original name made it distorted again.
Closing and re-opening the project makes no difference. Nor copying to a new move.
As I recall from those previous occasions, it's as if MEP falsely remembers details associated with a filename, despite that file being deleted from the project.
--
Terry, East Grinstead, UK