The API sometimes phrases the classes you have incorrectly. This throws an error and displays the incorrect results.
From my attempts, its been impossible to reproduce, but people have told me about this and I've seen the error messages. If anyone has any ideas why the API isn't working, feel free to make a pr, etc.
https://pastebin.com/wQc9DN3L
Appears to be related to when the API gets the classes your assigned to, but can't find a function that contains information.