Program: 61454
Project: 61454
Buggy source:
private static String convertTimeline(int spriteId,List<Integer> nonLibraryShapes,String backgroundColor,ReadOnlyTagList tags,ReadOnlyTagList timelineTags,HashMap<Integer,CharacterTag> characters,String name,FLAVersion flaVersion,HashMap<String,byte[]> files){
  StringBuilder ret=new StringBuilder();
  ret.append("String_Node_Str").append(name).append("String_Node_Str");
  ret.append("String_Node_Str");
  String labelsLayer=convertLabelsLayer(spriteId,tags,timelineTags,backgroundColor);
  ret.append(labelsLayer);
  String scriptLayer=convertActionScriptLayer(spriteId,tags,timelineTags,backgroundColor);
  ret.append(scriptLayer);
  int index=0;
  if (!labelsLayer.isEmpty()) {
    index++;
  }
  if (!scriptLayer.isEmpty()) {
    index++;
  }
  int layerCount=getLayerCount(timelineTags);
  Stack<Integer> parentLayers=new Stack<>();
  for (int d=layerCount; d >= 1; d--, index++) {
    for (    Tag t : timelineTags) {
      if (t instanceof PlaceObjectTypeTag) {
        PlaceObjectTypeTag po=(PlaceObjectTypeTag)t;
        if (po.getClipDepth() == d) {
          for (int m=po.getDepth(); m < po.getClipDepth(); m++) {
            parentLayers.push(index);
          }
          ret.append("String_Node_Str").append(index + 1).append("String_Node_Str").append(randomOutlineColor()).append("String_Node_Str");
          ret.append("String_Node_Str");
          ret.append("String_Node_Str");
          convertFrames("String_Node_Str","String_Node_Str",nonLibraryShapes,tags,timelineTags,characters,po.getDepth(),flaVersion,files,ret);
          ret.append("String_Node_Str");
          index++;
          break;
        }
      }
    }
    boolean hasClipDepth=false;
    for (    Tag t : timelineTags) {
      if (t instanceof PlaceObjectTypeTag) {
        PlaceObjectTypeTag po=(PlaceObjectTypeTag)t;
        if (po.getDepth() == d) {
          if (po.getClipDepth() != -1) {
            hasClipDepth=true;
            break;
          }
        }
      }
    }
    if (hasClipDepth) {
      index--;
      continue;
    }
    int parentLayer=-1;
    if (!parentLayers.isEmpty()) {
      parentLayer=parentLayers.pop();
    }
    String layerPrev="String_Node_Str";
    layerPrev+="String_Node_Str" + (index + 1) + "String_Node_Str"+ randomOutlineColor()+ "String_Node_Str";
    if (d == 1) {
      layerPrev+="String_Node_Str";
    }
    if (parentLayer != -1) {
      if (parentLayer != d) {
        layerPrev+="String_Node_Str" + (parentLayer) + "String_Node_Str";
      }
    }
    layerPrev+="String_Node_Str";
    String layerAfter="String_Node_Str";
    int prevLength=ret.length();
    convertFrames(layerPrev,layerAfter,nonLibraryShapes,tags,timelineTags,characters,d,flaVersion,files,ret);
    if (ret.length() == prevLength) {
      index--;
    }
  }
  int soundLayerIndex=layerCount;
  layerCount++;
  convertSoundLayer(soundLayerIndex,backgroundColor,characters,tags,timelineTags,files,ret);
  ret.append("String_Node_Str");
  ret.append("String_Node_Str");
  return ret.toString();
}

Fixed version (ground truth):
private String convertTimeline(int spriteId,List<Integer> nonLibraryShapes,String backgroundColor,ReadOnlyTagList tags,ReadOnlyTagList timelineTags,HashMap<Integer,CharacterTag> characters,String name,FLAVersion flaVersion,HashMap<String,byte[]> files){
  StringBuilder ret=new StringBuilder();
  ret.append("String_Node_Str").append(name).append("String_Node_Str");
  ret.append("String_Node_Str");
  String labelsLayer=convertLabelsLayer(spriteId,tags,timelineTags,backgroundColor);
  ret.append(labelsLayer);
  String scriptLayer=convertActionScriptLayer(spriteId,tags,timelineTags,backgroundColor);
  ret.append(scriptLayer);
  int index=0;
  if (!labelsLayer.isEmpty()) {
    index++;
  }
  if (!scriptLayer.isEmpty()) {
    index++;
  }
  int layerCount=getLayerCount(timelineTags);
  Stack<Integer> parentLayers=new Stack<>();
  for (int d=layerCount; d >= 1; d--, index++) {
    for (    Tag t : timelineTags) {
      if (t instanceof PlaceObjectTypeTag) {
        PlaceObjectTypeTag po=(PlaceObjectTypeTag)t;
        if (po.getClipDepth() == d) {
          for (int m=po.getDepth(); m < po.getClipDepth(); m++) {
            parentLayers.push(index);
          }
          ret.append("String_Node_Str").append(index + 1).append("String_Node_Str").append(randomOutlineColor()).append("String_Node_Str");
          ret.append("String_Node_Str");
          ret.append("String_Node_Str");
          convertFrames("String_Node_Str","String_Node_Str",nonLibraryShapes,tags,timelineTags,characters,po.getDepth(),flaVersion,files,ret);
          ret.append("String_Node_Str");
          index++;
          break;
        }
      }
    }
    boolean hasClipDepth=false;
    for (    Tag t : timelineTags) {
      if (t instanceof PlaceObjectTypeTag) {
        PlaceObjectTypeTag po=(PlaceObjectTypeTag)t;
        if (po.getDepth() == d) {
          if (po.getClipDepth() != -1) {
            hasClipDepth=true;
            break;
          }
        }
      }
    }
    if (hasClipDepth) {
      index--;
      continue;
    }
    int parentLayer=-1;
    if (!parentLayers.isEmpty()) {
      parentLayer=parentLayers.pop();
    }
    String layerPrev="String_Node_Str";
    layerPrev+="String_Node_Str" + (index + 1) + "String_Node_Str"+ randomOutlineColor()+ "String_Node_Str";
    if (d == 1) {
      layerPrev+="String_Node_Str";
    }
    if (parentLayer != -1) {
      if (parentLayer != d) {
        layerPrev+="String_Node_Str" + (parentLayer) + "String_Node_Str";
      }
    }
    layerPrev+="String_Node_Str";
    String layerAfter="String_Node_Str";
    int prevLength=ret.length();
    convertFrames(layerPrev,layerAfter,nonLibraryShapes,tags,timelineTags,characters,d,flaVersion,files,ret);
    if (ret.length() == prevLength) {
      index--;
    }
  }
  int soundLayerIndex=layerCount;
  layerCount++;
  convertSoundLayer(soundLayerIndex,backgroundColor,characters,tags,timelineTags,files,ret);
  ret.append("String_Node_Str");
  ret.append("String_Node_Str");
  return ret.toString();
}