can't relink files

I have a wedding editor, overseas, using fcpx. I sent him proxy files. Upon receiving the library, I can't relink the files because, according to the error message: the original file didn't have audio but the new file does.

This is wrong because I can very clearly hear audio on the files I sent.

I have used this editing company 16 previous times in the exact same manner and never had this problem. I sent files WITH audio but fcpx thinks I did not.

I transcode all my mp4 vids into proxy/optimized .mov files. The editor edits with the proxy, then I normally relink with minimal issues (not perfectly seamles but I eventually get them all linked. I just can't figure out what fcpx thinks my original videos didn't have audio.