Class compilation in TS when pluginBabel enabled not working as expected

[NikAtIdeally]

Im currently moving away from CRA/CRACO and I found unexpected behaviour with my app.
I was able to reproduce the behaviour with a new empty react app creating using create rsbuild

When adding pluginBabel to plugins in defineConfig it yields unexpected bundled js code.

Here is the TS code example that I have:

class MyClass  {
  public NUM = this.int;
  constructor(public int: number) {
    console.log("this", this);
  }
}

So when referencing an instance of this class from anywhere in the app I expect NUM to be === to this.int passed in constructor. And it works like this without the babel plugin. However when I add pluginBabel() to my plugins list it stops working.

Here is my rsbuild.config:

export default defineConfig({
  performance: {
    buildCache: false,
  },
  plugins: [
    pluginReact({reactRefreshOptions: {forceEnable: true}}),
    pluginBabel(),
  ],
});

So here is the compiled JS code without the plugin:

class MyClass {
    int;
    NUM;
    constructor(int){
        this.int = int;
        this.NUM = this.int;
        console.log("this", this);
    }
}

and here is what I see when I enable the plugin:

class MyClass {
    NUM = this.int;
    constructor(int){
        this.int = int;
        console.log("this", this);
    }
}

So it looks like its trying to set NUM before constructor is called. Which leads the value to be undefined.

Output of this:

So question is: Is this a me issue? Am I missing configuration or something?
Ive just tried Vite (and their hot reload did not work for me), and did not have issues with their babel plugin. 🤷‍♂️ Any advice would be great. not too keen on having to go back to CRA.

Thank you.

[NikAtIdeally]

Alright. I think I figured it out.
Couple of things to get it to work.
Add @babel/plugin-transform-class-propertiesas a last plugin to babel plugins.
And I had to disable react reload as it went into an infinite reload loop. HMR still works however.

Solution is less then ideal, and it would be great if this was resolved properly, but it works now.