Thymeleaf and th:if not skipping text when null

I understand that you should be able to "skip" text printing if Object is null, in thymeleaf, using th:if.

However my page throws Null error at line 23. (second div)

        <div th:if="${Brackets}">
            <th:block th:each="brackets : ${Brackets}">
                <div th:if="${brackets.brackets}">
                    <tr th:each="bracket : ${brackets.brackets}">
                        <td th:text="${bracket.lower}"></td>
                        <td th:text="${bracket.higher}"></td>
                        <td th:text="${bracket.prc}"></td>
                    </tr>
                </div>
            </th:block>
        </div>

What am i missing here?