Yes, if there was an error trying to read the file we’d see this error in the simulator and I don’t think that’s the case here. Normally the game goes through all files in the import folder and opens them. My assumption is that this is where it fails so it doesn’t even see the file. There’s some extra logic with combining two different directories in the SDK so a couple of things could be happening and it’s hard to tell with remote debugging.
I think it's an off-by-one SDK bug in playdate.file.listFiles. If I give it a directory with one file, it just returns "../". If I add one dummy, it gives me rdk.json and not the dummy file. Reported upstream here: https://devforum.play.date/t/playdate-file-listfiles-only-showing-some-files/356...
If it gets no response, I'll open a new bug rather than reply to an old one.