For some reason a variable was not set correctly in one of the cases. Now it set.

It happened when you talked with Velma about training for the restaurant and you already showed her the magic bust. This blocked you form being able to train her. If Velma keeps getting insulted while serving and you don't have the option to train her, open the debug menu and run the command "setCar Velma BrothelStory 1.6" if you don't want to start a new save