Huh, found an interesting bug that only seems to show up between Goofys (s3fs alternative) and Subsonic Music server, barring some more testing.

When a podcast tries to download with its target being the Goofys mount point, it downloads only a 320 KB file named with some UUID looking format, and isn't valid audio. If the podcast downloads to local storage, no prob!

Was using s3fs fuse until recently, need to test Subsonic against that to confirm if its Goofys at fault...