The new on_title_changed function follows the same pattern as on_status_changed and on_severity_changed, which both have dedicated test classes in test_hooks.py. However, on_title_changed is not imported in the test file and has no corresponding tests. While it's mocked in test_channel_commands.py, this only verifies callers don't crash—it doesn't test the hook's actual behavior (posting messages, updating topics, handling missing Slack links).

The handle_mitigated_submission function performs two sequential serializer.save() calls (status at line 101 followed by description at line 115) outside of a database transaction. If the first succeeds but the second fails, the incident will be marked as 'Mitigated' but the mitigation notes won't be appended to the description, leaving the incident in a partially-updated state with no record of the impact/action items that were collected.