Problems with Mix and webpack-dev-server -

I'm struggling to get Laravel Mix and webpack-dev-server working together correctly. Mix works fine for bundling assets to files, and using "watch" mode also works correctly.

When I try using it with webpack-dev-server, I hit problems. The in-memory "build" seems to works, and the dev-server is serving up assets (so not a cache problem) - but it's serving stale ones from storage, rather than the in-memory versions. If I change a source file I see the rebuild in the console, but still the stale assets get served if I hit F5. (The stale assets are from a previous 'regular' Laravel mix build)

More details on SO below. Not sure if SO or this forum is the best place to ask this...

https://stackoverflow.com/questions/52831164/laravel-mix-and-webpack-dev-server-changed-files-not-refreshing