Getting rid of inter-stage transitions

[THEkatinamicrowave]

I'm making a mod and I have a transition between two stages but it fucks up when PlayState.instance.endSong() runs because for some reason it decides to blip out of existence when the stage switches. Here's a video:

2026-06-09.13-45-23.mp4

Would love it if someone could please give me some insight on this and how to stop it from happening