Menus are transparent, is this a bug or intentional? (Plasma 6)

<img width="588" height="506" alt="Image" src="https://github.com/user-attachments/assets/686e03d2-279d-4d3e-9468-ad0fe19900fc" />
<img width="492" height="476" alt="Image" src="https://github.com/user-attachments/assets/455d745a-f56d-44bf-ab31-29c023662b23" />

any idea why?