[bug] Sticky header flickers on refresh when page is scrolled

### URL: https://nodejs.org/docs/latest/api/assert.html ### Browser Name: Brave ### Browser Version: 1.89.132 ### Operating System: macOS Tahoe 26.2 ### How to reproduce the issue: 1.I opened https://nodejs.org/docs/latest/api/assert.html in my browser and then scrolled to around the middle of the page, and refreshed the tab. 2.I expected the sticky header area (Node.js v25.x, Table of contents, Index, Other versions, Options) to stay in the same compact/pinned state immediately after refresh, without any visual jump. 3.The header briefly appears in a larger/unpinned layout for a fraction of a second right after refresh, then snaps back to compact/pinned state, causing a noticeable flicker/jump. 4.I can attach screenshots/video. The flicker is easier to notice when refreshing while scrolled down. https://github.com/user-attachments/assets/4a6167ab-881d-4ab4-8c24-126fefb23e4a