Vue cli 5 not building chunk-vendors.css in production mode

Question

After updating my vue cli version to 5.0.1 I had tried to build my app using both dev mode and production mode. I use code splitting and have many files dynamically imported to move into their own chunks. Before on the vue-cli V4 on production it would generate both a chunk-vendors.js and chunk-vendors.css with the rest of the files. I also added

css: {
    extract: {
        filename: 'css/[name].css',
        chunkFilename: 'css/[name].[contenthash].css',
    },
},

to allow for css to be extracted in dev mode. After updating to vue-cli V5 in dev mode everything is still generated correctly. But in production mode chunk-vendors.css doesnt get generated. It still generates chunk-vendors.js for some reason.

I did notice that it instead produces a large number of build/js and build/css files instead with a file name like 1828.ee90da537ad55686.js or 1828.ee90da537ad55686.css. This makes me think its instead making these files instead of chunk-vendores.

I have tried looking all over the docs for Webpack 5 and Vue-Cli 5 for breaking changes and changes involving css or css extraction but no luck on finding a reason.

Any possibilities to look for?