It’s surprisingly common for commercial DVDs to be badly mastered, with mismatched aspect ratio information in the DVD container vs. the video stream. My guess is that the Fire is ignoring the container and only looking at the stream.
This may be helpful, or it may be backwards. I can’t tell which issue the file has from the description given:
Color Cartoon Aspect Compression - but not in B&W! - #13 by Volts
Share the file if you’d like me to look.
