If this is only happening in courses that were copied from a previous install, then there are a couple of places you can look for differences:
- Check if there are any weird settings in course.conf or simple.conf.
- Check the templates/macros directory to see if there are any local copies of macro files that behave differently than the ones from pg or the OPL.
With that being said, if your newly created courses don't have this problem then it's probably easier to stick with those.