Setting text field in create fails on Dexterity

The following code fails on Dexterity-based content types (plone.app.contenttypes):

with api.env.adopt_roles(['Manager']):
    obj = api.content.create(
        container=portal,
        type='Document',
        title=u'Pangram',
        text=u'<p>The quick brown fox jumps over the lazy dog</p>',
    )

on Archetypes, the text field is set; on Dexterity, the text field is set as a unicode object leading to the following error:

AttributeError: 'unicode' object has no attribute 'output_relative_to'

the workaround is something like:

def set_text_field(obj, text):
    try:
        obj.setText(text)  # Archetypes
    except AttributeError:
        obj.text = RichTextValue(text, 'text/html', 'text/html')  # Dexterity

where do we handle this? here or in plone.app.contenttypes?

Start by inspecting api.content.create and how it sets fields for Archetypes versus Dexterity-based types from plone.app.contenttypes. Reproduce the issue with the provided Document example and compare it with the setText and RichTextValue workaround. Done means creating the Document with text no longer leaves a raw unicode value that raises output_relative_to.