What causes audio files to corrupt in Notes app on my iPhone?

I recorded two phone calls today. Both saved in notes as usual and both played back. I tried sending one of the audio files to my computer for easier playback but it fails to airdrop and when I try saving it to files it starts "processing" but freezes about 1/4 of the way in. I try the same with the second recording. Same result. When I go back to the first recording again to play it on my phone, it no longer works. It has lost the playback button. It has no transcript. It looks like an audio file is there but nothing happens when I click it. Neither of these files (the one that plays on my phone and the one that doesn't) will play or even open on Notes on the mac. They're showing up there with the name of the file and an image of the music app icon. But it's like they saved as jpegs instead of audio files. Files from a week earlier do not have any of these issues. Apple chat spent 2.5 hours having me update the software on my phone and deleting and reinstalling Notes. Didn't work HELP! I need to be able to hear that first file. I don't care where at this point. I'll try anything! Photos of how the file I cannot play anywhere looks on my phone and computer are below.

[Re-Titled by Moderator]