If QSortFilterProxyModel::setFilter* removes an item which was selected, the beginRemoveRows in QSortFilterProxyModelPrivate::remove_proxy_interval triggers a QItemSelectionModel::selectionChanged. If in response to that dataChanged is called on the source model, QSortFilterProxyModelPrivate::remove_proxy_interval is called again and when the stack returns to the first invocation, the proxy intervals are not valid anymore.

tl;dr: changing the source model due to signals emitted during setFilter* crashes