An image placed on a recording is stored as a position and a box measured against the frame, and the share page draws the image to fit inside that box without distorting it. The download was instead stretching the image to fill the box exactly, so the same edit looked right on the share link and squashed or stretched in the downloaded file.
The download now fits and centres the image in its box the same way the share page does. Recordings with images that had already been downloaded will re-encode the next time they are downloaded.