After multiple trials to determine the most effective flipped classroom design for our bachelor course, Philosophy of Science, we established a setup with compulsory flipped workgroups at the core, while online knowledge videos and optional joint classes offer preparatory support. This article documents our attempts to improve scaffolding offered in the optional joint classes by structuring them according to the Question Driven Discovery model. Regarding the effectiveness of the offered scaffolding, the findings are mixed: students did not perceive the joint classes as highly activating or yielding positive learning effects, and most preferred to prepare for flipped workgroups independently. However, substantial differences were noted in learning activities and outcomes between attendees and non-attendees, as well as in their valuation of the supportive and activating function of the joint classes. These results confirm earlier findings which show that, to capitalize on the potential activating effect of the flipped classroom during the bachelor phase, instructors need to strike the right balance between structure and flexibility. As early career students' capacity to self-regulate is limited, we recommend future research focuses on how to design assignments and assessment in such a way that students are required to engage in scaffolding learning activities, even if they are non-compulsory.