Conquering fundamental programming concepts that subtly affect program behavior is a challenge for Computer Science (CS) students. Learning parameter passing, aliasing, scope, and references, how they work and being able to reason about them, is crucial for CS students. In this qualitative study we explore how these concepts are taught from the perspective of Teaching Assistants (TAs). Using phenomenographic analysis we find several areas that could be improved regarding the activities and assessments that students are exposed to during their studies. These findings include issues with consistent grading, the training of TAs, the support structures offered to TAs, and variations in the perceived focus on these concepts. Finally, our results highlight a need to explore how proficient TAs are with these concepts.