I tried inserting a definition list in my contents.lr file.
Tables are working fine but the definition lists are not handled correctly.
Example taken from https://pythonhosted.org/Markdown/extensions/index.html
Apple
: Pomaceous fruit of plants of the genus Malus in
the family Rosaceae.
Orange
: The fruit of an evergreen tree of the genus Citrus.
Rendering the string directly with markdown works:
markdown.markdown(s, extensions=['markdown.extensions.def_list'])