I'm running this for loop and modifying some values on the go. It logs the values changed correctly in each iteration, but it repeats the last iteration when writing to sheets.

const rngList = cadSheet.getRangeList(dataRng).getRanges();

  //Gets the ranges' values and push them into an array;
  let values = [];
  for (let i = 0; i < rngList.length; i++) {
    values = [].concat(values, rngList[i].getValues().flat());
    //values.push([rngList[i].getValue()]);
  }

  let itens = [];
  for (let a = 0; a < tamanhosEscArr.length; a++) {
    for (let r = 0; r < coresEscArr.length; r++) {
      values[4] = variacao++;//Increments an ID number
      values.splice(29, 1); //removes this element
      values.splice(29, 0, tamanhosEscArr[a]); //inserts size being iterated over

      values.splice(30, 1);//removes this element
      values.splice(30, 0, coresEscArr[r]); //inserts color being iterated over

      Logger.log('Item: ' + values) //logs all 18 or so items, with their corresponding sizes and colors
      itens.push(values);
    }
  }
  suporteSheet.getRange(suporteSheet.getLastRow() + 1, 1, itens.length, itens[0].length).setValues(itens); //Writes the last iteration as many times as the iterations (18)

This is the log, showing the correct result:

This is how this is writing to the spreadsheet:

I can't see where the flaw is here, besides my existence.

Thanks for the light!