Browser window didn't actually meet the criteria and was deleted. In the logs it says in the deletion reason was "Not a game", but there could be many other minor reasons why it was deleted, which I usually didn't put as I only needed one major violation to prune an entry.
You can find a list of deleted entries here: https://docs.google.com/spreadsheets/d/1ch8XFmhJEJ_knJ9XIzNr1AVqOZvtzXvWucfj9yZi...