Docs pages' On This Page / Table of Contents doesn't work correctly on Chromium-based browsers for certain pages

The On This Page feature for docs' pages is supposed to follow the header whose content more or less the current focus of the page. However, on Chromium-based browsers this seems offset in the beginning and not working entirely correctly on certain pages.

Video on Firefox (where it works as intended):
https://github.com/bevyengine/bevy-website/assets/31419708/3c356c28-a3dd-437e-948a-0f2d9f286e06

Video on Chromium (where it seems wonky, at least in the beginning):
https://github.com/bevyengine/bevy-website/assets/31419708/e47a4ba1-50bf-404c-ac7e-e7365e148640

Pages noted as affected so far: , , and .

Edit: First noticed on Discord [here]().

Reproduce the On This Page behavior in Chromium and Firefox on the three affected pages: entities-components, getting-started, and 0-13-to-0-14. Start by locating the website's On This Page or table-of-contents implementation and compare the initial and scrolling header selection between browsers. Done means the highlighted header follows the page focus consistently in Chromium as it does in Firefox.

Written by the indexing model from the issue text.