Use of the stepsection element nested in a steps-unordered element

Hello,

I am working with DITA in FrameMaker 2017, I have a question concerning the use of a stepsection element in a task topic.

I am trying to use the stepsection element nested in a steps-unordered element to introduce an unordered list. But the result is not what I expect to be.

My structure view looks like this :

taskbody

     steps-unordered

          stepsection

               p

          step

          step

But as a result, the paragraph is bulleted and is considered as the first element of the list.

The same stepsection nested in a steps element works fine since I am able to add a simple paragraph above the steps to introduce the procedure.

My structure looks like this :

taskbody

     steps

          stepsection

               p

          step

          step

As a result, the paragraph introducing the list is not part of the numbered list, as exêcted.

Could anyone tell me if there is Something wrong with the structure of my unordered list?

Thank you in advance for helping.

Vanessa.