Fixed

source/funkin/backend/chart/ChartData.hx

@@ -51,7 +51,6 @@ typedef ChartNote = {
 	var id:Int; // strum id of the note
 	var type:Int; // type (int) of the note
 	var sLen:Float; // sustain length of the note (ms)
-	var ?extra:Map<String, Dynamic>;
 }
 
 typedef ChartEvent = {

source/funkin/game/Note.hx

@@ -117,7 +117,11 @@ class Note extends FlxSprite
 		this.isSustainNote = sustain;
 		this.sustainLength = sustainLength;
 		this.strumLine = strumLine;
-		this.extra = noteData.extra;
+		for(field in Reflect.fields(noteData)) {
+			if(!["time", "id", "type", "sLen"].contains(field)) {
+				this.extra.set(field, Reflect.field(noteData, field));
+			}
+		}
 
 		x += 50;
 		// MAKE SURE ITS DEFINITELY OFF SCREEN?