I wonder if Match would have caused it to silently re-upload your missing files then supply them back.

It's the (supposed, it's very confusing) difference between Match as a standalone service and the Apple Music streaming service when it comes to your own library--Match will serve back your own music files to you if not already on the service. OTOH, I have no idea what it does if it thinks it matched on the service when first scanned, but the track isn't there anymore.