The old code registered a Shiboken converter for PyObjectWrapper by pointer conversion. This resulted in the Python to C++ converter falling back to plain pointer passthrough since it only works for SbkObjects. The C++ to Python conversion worked by coincidence for either raw PyObject * pointers used in meta call handling or pointers obtained from calling QVariant<PyObjectWrapper>.data(), but without handling reference counts. To fix this, remove the Python to C++ conversion entirely and do this manually via QVariant. Change the C++ to Python to be by value and use PyObjectWrapper. Fixes: PYSIDE-2193 Change-Id: I00898894651f220d7b8fe60608e93233ef3e6493 Reviewed-by: Shyamnath Premnadh <Shyamnath.Premnadh@qt.io> (cherry picked from commit 62e72aa6db6af546aa6a96be027e6f0c57cd8f3e) Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>