This happens fairly often on leg days, especially if I have increased the weight after a deload. In this case, it was the romanian deadlifts that did it.

As far as the project goes, I need to figure out the proper webpack config for it. The bundle.js file is way too large, and I assume it has something to do with the way webpack.config.js is set up. I'll figure it out tomorrow when my legs are sore instead of cramped.