I have the following heading in my content:
What you’ll learn

My CMS output:

<h2 id="what-you%E2%80%99ll-learn" tabindex="-1">What you’ll learn</h2>

Clicking on the corresponding toc link throws an error and tocbot stops working correctly.
The error:
Uncaught SyntaxError: Failed to execute 'querySelector' on 'Element': '#what-you%E2%80%99ll-learn' is not a valid selector

It looks like querySelector doesn't handle these special characters very well, but it seems that getElementById doesn't have the same problem.

I'm using v4.35.0.
Tested on Brave, Safari, and Firefox.