Chartjs-DevTools failed to load source map, chart.js behaving abnormally

Ok, classic rookie mistake. Big surprise, I know. It turns out that chart.js just updated to v4.0.1 two days ago, and includes some breaking changes.

So I pinned the version of chart.js that my site uses:

<script src="https://cdn.jsdelivr.net/npm/chart.js@3.9.1"></script>

I guess another option would be to host the libraries locally, but ain’t nobody got time for that. I’m going to mark this as answered.