Weird bug with code splitting on initial page load

[Bram-Zijp]

When I load page 1 with chunks: main.js main.css 1.js 1.css and I change something part of chunk 1.css, the main.css gets reloaded.
When I load page 1 then navigate (with react-router-dom) to page 2 wich adds 2.js 2.css to the head, and I change something in 2.css, 2.css is hot reloading fine.

I'm using react-loadable to split chunks automatically but this probably unrelated.

"css-hot-loader": "^1.3.9",
 "mini-css-extract-plugin": "^0.4.0",
"webpack": "^4.6.0",
"react-loadable": "^5.3.1",

[ScriptedAlchemy]

faceyspacey/extract-css-chunks-webpack-plugin#80

[shepherdwind]

#44