unnestDDBJson in Glue throws when using UUIDs as map keys in Dynamo items

Hi!

I'm having some issue processing a DynamoDB export in Glue. It looks like my schema is breaking DynamicFrame's unnestDDBJson transformation.

This is the minimal test case that will trigger the error:

import com.amazonaws.services.glue.{DynamicFrame, GlueContext}
import com.holdenkarau.spark.testing.SharedSparkContext
import org.scalatest.flatspec.AnyFlatSpec

class DynamoUnnestTest extends AnyFlatSpec with SharedSparkContext {
  "DynamoDB unnest" should "work" in {
    val glueContext = new GlueContext(sc)
    val spark = glueContext.sparkSession

    import spark.implicits._

    val ddbItem =
      """
        |{
        |  "Item": {
        |    "PK": {
        |      "S": "PFL/XPAR/EUR"
        |    },
        |    "Obj": {
        |      "M": {
        |        "FiMap": {
        |          "M": {
        |            "3659288a-0b41-4bf5-ac7f-a379fafa5576": {
        |              "M": {
        |                "DT": {
        |                  "S": "2023-05-25"
        |                }
        |              }
        |            }
        |          }
        |        }
        |      }
        |    }
        |  }
        |}
        |""".stripMargin

    val df = spark.read.json(Seq(ddbItem).toDS).toDF()
    val dyf = DynamicFrame.apply(df, glueContext)

    // This fails with exception:
    // org.apache.spark.sql.AnalysisException: No such struct field 3659288a in 3659288a-0b41-4bf5-ac7f-a379fafa5576;
    dyf.unnestDDBJson()
  }
}

Any idea if I'm doing something wrong? Or could approach it differently somehow?