Why does Laravel’s getMimeType() method identify a file as “application/octet-stream” when the file has the type attribute of “audio/mpeg”?

I’m trying to upload a MP3 file to a Laravel application and have ran into an issue where even though the file has an attribute set to “audio/mpeg” it is uploaded as a “application/octet-stream” (.bin) file. When I try to die and dump the file on the server-side code with: