FSM6u24: How to Hierarchy select with Variable Date Constraint?

All,

Is there a way to Hierarchy select with a variable date? 

Static dates work fine, but I cannot figure out how to put a variable date in a hierarchy select

I tried a variety of expressions & variables without luck, such as: 

• Today()
• @expression[Today()]
• @expression[Now()]
• another dttm column (such as task.plan_end_dttm)

This works as intended, with a static date value:

<hierarchy_select>
  <attrs>
    <attr>task.task_id</attr>
  </attrs>
  <primary_table>task</primary_table>
  <from>
    <table>task</table>
  </from>
  <where>
    <data_constraint>
      <constraint>
        <left_operand>task.plan_start_dttm</left_operand>
        <operator>gt</operator>
        <right_operand>4/26/2024</right_operand>
      </constraint>
    </data_constraint>
  </where>
</hierarchy_select>

This is what I’m trying to accomplish, which I cannot get to work

Sample 1 (variable)

    <hierarchy_select>
        <attrs>
            <attr>task.task_id</attr>
        </attrs>
        <primary_table>task</primary_table>
        <from>
            <table>task</table>
        </from>
        <where>
            <data_constraint>
                <constraint>
                    <left_operand>task.plan_start_dttm</left_operand>
                    <operator>gt</operator>
                    <right_operand>@expression[Today()]</right_operand>
                </constraint>
            </data_constraint>
        </where>
    </hierarchy_select>

 sample 2 (from dttm field)

<hierarchy_select>
        <attrs>
            <attr>task.task_id</attr>
        </attrs>
        <primary_table>task</primary_table>
        <from>
            <table>task</table>
        </from>
        <where>
            <data_constraint>
                <constraint>
                    <left_operand>task.plan_start_dttm</left_operand>
                    <operator>gt</operator>
                    <right_operand>task.plan_end_dttm</right_operand>
                </constraint>
            </data_constraint>
        </where>
</hierarchy_select>

The error returned is: 

<metrix_response>
  <result type="Exception">
    <error>
      <system_error>
        <severity>ERROR</severity>
        <message>The following system level exception was generated by the application: String was not recognized as a valid DateTime.
Contact your system administrator for assistance. The server log or event log may contain more details about the error.</message>
      </system_error>
    </error>
  </result>
</metrix_response>

Appreciate any feedback