Update

Source/FLESH/FLESH.Build.cs

@@ -11,6 +11,7 @@ public class FLESH : ModuleRules
 		PublicIncludePaths.AddRange(
 			new string[] {
 				// ... add public include paths required here ...
+				"$(EngineDir)/Plugins/Experimental/GeometryScripting/Source/GeometryScriptingCore/Public"
 			}
 			);