How to change paragraph style used for stepsection in EDD?

I need to use the stepsection element in task topics (DITA 1.3) for paragraphs that are not formatted as lists. My topic looks as follows:

<task id="id123"><title>Working with sample files</title>
<abstract>Sample files are provided as example and can be used in
a variety of ways.</abstract>
<prolog><author></author></prolog>
<taskbody><steps-unordered><stepsection>You have the following options:</stepsection>
<step><cmd>The files can be opened, edited or copied.</cmd></step>
<step><cmd>The files can be deleted or moved.</cmd></step>
<stepsection>Only in case of exemplary administration rights, the
following options are displayed:</stepsection>
<step><cmd>You can share the sample file with other example users.</cmd></step></steps-unordered></taskbody></task>

Now, I would expect the stepsection element to always assigned to paragraph style "Haupttext" (body? in English?) and not be part of the list. The result looks like this though:

The stepsection that comes before the first step is formatted as the first item of the list though (paragraph style "unorderedstep.begin"). Only the stepsection that is after a step is formatted correctly (paragraph style Haupttext/body).

This actually looks like a bug to me, because I can't imagine why you would need a stepsection as the first item of the list. (I've found a post about it from some years ago, but it hasn't changed...)

How can I change this?

(I couldn't find stepsection in task.edd.fm or commonElements.eddmod.fm. So far, I've only had to change simple things in these files.)