\begin/\end{eqnarray*} should be a block element

I get 

<img width="826" alt="Image" src="https://github.com/user-attachments/assets/f70725c6-410a-449a-9545-f7b077f53dca" />
in `MathHub/courses/FAU/SMAI/problems/source/math/quiz/defeq1.en.tex`. 