diff --git a/MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/FeatureLib/pfPython/plPythonSDLModifier.cpp b/MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/FeatureLib/pfPython/plPythonSDLModifier.cpp
index 9107ee55..14904436 100644
--- a/MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/FeatureLib/pfPython/plPythonSDLModifier.cpp
+++ b/MOULOpenSourceClientPlugin/Plasma20/Sources/Plasma/FeatureLib/pfPython/plPythonSDLModifier.cpp
@@ -192,6 +192,22 @@ void plPythonSDLModifier::SetItemIdx(const char* key, int idx, PyObject* value,
 		return;
 	}
 
+	if (pyTuple && pyTuple->ob_refcnt != 1)
+	{
+		// others already have references to the tuple and expect it to be immutable, must make a copy
+		int n = PyTuple_Size(pyTuple);
+		PyObject* newTuple = PyTuple_New(n);
+		for (int j = 0; j < n; j++)
+		{
+			PyObject* item = PyTuple_GetItem(pyTuple, j);
+			Py_INCREF(item);
+			PyTuple_SetItem(newTuple, j, item);
+		}
+		Py_DECREF(pyTuple);
+		pyTuple = newTuple;
+		it->second.obj = newTuple;
+	}
+
 	if (pyTuple)
 	{
 		if (PyTuple_Size(pyTuple) <= idx)
@@ -205,6 +221,8 @@ void plPythonSDLModifier::SetItemIdx(const char* key, int idx, PyObject* value,
 				Py_INCREF(Py_None);
 				PyTuple_SetItem(pyTuple, j, Py_None);
 			}
+			// _PyTuple_Resize may have changed pyTuple
+			it->second.obj = pyTuple;
 		}
 	}
 	else