Sweet!
Does the custom node call a specified Python function from inside the
draw method? If so, you will need to make sure the plugin acquires the Python global interpreter lock before triggering the Python code. This might be the cause of the crashes you mention. Example:
Code:
PyGILState_STATE pyGILState = PyGILState_Ensure();
//Run Python code
PyGILState_Release(pyGILState);