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Bug Description

When using CSS experiments in prod build
animation: none !important gets converted to animation: none !DfLy9m

Link to Minimal Reproduction and step to reproduce

webpack.config.js

export default {
    mode: 'production',
    entry: "./index.css",
    experiments: {
        css: true,
    },
    module: {
        rules: [
            {
                test: /\.css$/i,
                type: "css/module",
            },
        ],
    }
}

index.css:

.foo {
    animation: none !important;
}

the first !important stays as is, the second is changed.

Expected Behavior

!important is not treated as name and is never renamed.

.Fy_rS4 {
    animation: none !important;
}

Actual Behavior

!important gets renamed in animation property.

.Fy_rS4 {
    animation: none !kFtQY8;
}

Environment

webpack 5.106.0

Is this a regression?

None

Last Working Version

No response

Additional Context

No response