I recreated the problem with a song less than 4k characters, but more than 3k characters, the video is here.@Aviendha We were not able to reproduce this bug on our side. Due to it, that is possible glitch happened on your side. Try to restart the game and repeat same actions.
If issue remains, please record a short video, with the steps you complete that are causing a bug. We’ll then try to reproduce that bug on our side. That will help us to understand the root of the issue and the ways that can have it fixed.
Seems it happens with editing a song that is longer than the original max amount of characters?