"Leur beau-père est un homme important."
Translation:Their stepfather is an important man.
The course is entirely human-generated, with half a dozen contributors and thousands of sentences. It's only natural that it will be inconsistent in places. You should report any inconsistencies as soon as they come up, via the "report" button.
In this course, "père" should only be "father" and "papa" should only be "dad", "daddy", "pa", etc.