Running in Docker, regeneration issues

I am experimenting running my Jekyll site in a Docker container. This is in Ubuntu on Windows under WSL2, though I don’t think that matters. The command I am using is

$ docker run --rm --volume="$PWD:/srv/jekyll" -p 4000:4000 -it jekyll/jekyll jekyll serve

That works, the site launches fine, I can browse to it locally, all that jazz. The issue I am running into is that the site only regenerates if I make changes to the html files in the root directory. If I change any of the CSS files, anything in any sub directories, etc, nothing happens. I can force it by changing and saving any file in the root directory though. Here’s the final output I get then the container is done building and all that.

ruby 2.7.1p83 (2020-03-31 revision a0c7c23c9c) [x86_64-linux-musl]
Configuration file: /srv/jekyll/_config.yml
            Source: /srv/jekyll
       Destination: /srv/jekyll/_site
 Incremental build: disabled. Enable with --incremental
                    done in 0.393 seconds.
                    Auto-regeneration may not work on some Windows versions.
                    Please see:
                    If it does not work, please upgrade Bash on Windows or run Jekyll with --no-watch.
 Auto-regeneration: enabled for '/srv/jekyll'
    Server address:
  Server running... press ctrl-c to stop.

This bottom of this docker Jekyll article uses --watch explicitly, so see if that helps

I also like to use --livereload to force the browser to refresh.

Can you share a link to your repo and I’ll run to see if I can reproduce your problem