Mantaflow likes to throw exceptions when things go wrong, which includes a simple case of the solver not converging sufficiently. This should not be catastrophic, but cleanup of buffers is omitted when such an exception occurs. This then leads to yet another failure when the solver is stopped because of incorrect buffer refcounts. That exception bubbles up through the python layer and causes errors in the Blender integration wrapper that cause crashes. Pull Request: https://projects.blender.org/blender/blender/pulls/147527