The fire effect seems to freeze up with no way to trace how. I tried certain settings that affect world generation and enable certain things like Wild Update stuff and Gametest Framework and got no lead still. I'm not sure what caused it but it was after I fought the Wither twice to test FPS and while rain was happening that didn't vanish after setting the weather to clear. The only other reason is that it's related to the world settings for features, which "Wild Update", "Vanilla Experiments", and "Gametest Framework" were enabled with "Fancy Graphics" disabled.