I am a moderator for a mario maker streamer. Today, on YouTube, a lot of people were submitting levels. Nightbot registered everyone’s levels in the queue, except from one person. As far as I know, he followed the rules without a single time-out.
He submitted a level, nightbot said that it was added to the queue. However, it wasn’t registered in warp.world and when using !list, nightbot said that the person didn’t submit a level.
Since your using a Custom API you would need to reach out to that author. It’s also possible that Nightbot’s command cooldown was active, where the maximum you can call a command is once every 5 seconds. With YouTube, all messages are received in batches so the cooldown might have been active from the message before.