Serializing list of Files with gson not working in Android 12+ (API 32, 33)

Question

I do have an object with a list of Files (java.io.File):

class NewRequestBody {
    val files: MutableList<File> = ArrayList()
}

I need that object in my WorkManager class, so I use Gson to convert it to Json and add it to the WorkRequest.Builder as InputData:

val inputData = Data.Builder().putString(BODY_KEY, Gson().toJson(body)).build()

val myWorker = OneTimeWorkRequest.Builder(MyWorker::class.java)
      .setInputData(inputData)
      .build()

Then in my WorkManager class I'm converting it back:

val body = gson.fromJson(inputData.getString(BODY_KEY), NewRequestBody::class.java)

So far, with compileSdkVersion 30, that worked perfectly fine. The json hold this information for the files:

"files": [
    {
        "path": "path_to_the_file"
    }
]

However, after updating the targetSdkVersion and compileSdkVersion to 33, that doesn't work anymore. The json now holds just an empty array:

"files": [
    {}
]

Any idea what this is the case and how to fix it?