Hardcore "Delete world" button breaks other worlds

After dying in hardcore and pressing the delete world button, the world stays in the single-player world list. More importantly, even after deleting it from the world list, all worlds created after glitch in multiple ways. Most notably biomes change abruptly at the chunk borders and the time of day flashes between the time of the world just created and the previously deleted hardcore world. I did not test this with an existing world for fear of corrupting it.