I'm helping a developer of an app post this on their behalf. Can you please help out with this?
The bug is, when the first URL is used, sorting works correctly. But the movies,shows (aka item type) is an optional parameter, hence when omitted (as seen in the second url) sorting should work. But it does not and instead it returns the default sort and the sorting headers are also incorrect. You can replace the xxx/lists/xxx with any list of your choice.
https://api.trakt.tv/users/xxx/lists/xxx/items/movies,shows/title/asc?page=1&limit=1000&extended=full -> sorting works
https://api.trakt.tv/users/xxx/lists/xxx/items/title/asc?page=1&limit=1000&extended=full -> sorting broken
Can you provide any insight on anything can be done on the developer's side or is this definitely a bug on trakt's end that needs fixing?
Please let me know if you have any questions or need any other details.