I have a Samsung Galaxy S8 running Android 9 (at least currently - I don't know when that update took place, so I don't know if it is responsible for this issue). I have always had my ringtones (in mp3 format) in a folder on my internal storage, and my music (also mostly mp3) on my SD card. Sometime in the past year, an update caused my ringtones to stop working. They would not play at all, even when trying to preview them in the ringtone selector. Instead, the default ringtone would always play.
After some trial and error, I discovered that I could only get my ringtones to work if I put them on my external SD card.
Has anyone else seen this issue? Is there a way to fix it? It's very annoying, and messes up my file organization and management.