Vanishing sticky navbar in Safari

If I try to scroll "up" (i.e. trying to load content above what's already there), the sticky navbar vanishes, and there is no way to bring it back (except by reloading the page). The issue appears only in Safari and the navbar works fine in Firefox and Chrome.

<img width="1919" alt="Image" src="https://github.com/user-attachments/assets/c6c04e1e-47a7-4931-8bf0-3c47dcc5d38e" />