Unable to update score audio

I tried to update a score I had already published, which I had done fine multiple times before, but the musescore app no longer gives me the option to update the existing score (https://musescore.com/xiloscient/quiet-and-falling).
I was able to update the score itself by uploading the mscz file, but I couldn't find a way to upload the new audio, which leads to it desyncing at measure 65.