Subtheme issues

I created a subtheme off a Platon for my Opigno site, and it worked great. However, I noticed the other day that if you go to a courses and the click a course, the course page doesn't use the subtheme. Instead, it reverts back to Platon. I suspect it has something to do with how the Opingo Learning Path module installs, as its installation files references Platon in the installation files. Is there a way to override these settings so the entire site uses the subtheme? Best, Marc