Program: 69524
Project: 69524
Buggy source:
@Override protected Task stepGrading(UserRequest ureq,Task assignedTask){
  assignedTask=super.stepGrading(ureq,assignedTask);
  if (businessGroupTask) {
    String userLog=courseEnv.getAuditManager().getUserNodeLog(gtaNode,getIdentity());
    if (StringHelper.containsNonWhitespace(userLog)) {
      mainVC.contextPut("String_Node_Str",userLog);
    }
 else {
      mainVC.contextRemove("String_Node_Str");
    }
  }
  if (config.getBooleanSafe(GTACourseNode.GTASK_ASSIGNMENT) || config.getBooleanSafe(GTACourseNode.GTASK_SUBMIT) || config.getBooleanSafe(GTACourseNode.GTASK_REVIEW_AND_CORRECTION)|| config.getBooleanSafe(GTACourseNode.GTASK_REVISION_PERIOD)|| config.getBooleanSafe(GTACourseNode.GTASK_GRADING)) {
    if (assignedTask == null || assignedTask.getTaskStatus() == TaskProcess.assignment || assignedTask.getTaskStatus() == TaskProcess.submit || assignedTask.getTaskStatus() == TaskProcess.review || assignedTask.getTaskStatus() == TaskProcess.correction || assignedTask.getTaskStatus() == TaskProcess.revision || assignedTask.getTaskStatus() == TaskProcess.solution) {
      mainVC.contextPut("String_Node_Str","String_Node_Str");
    }
 else     if (assignedTask.getTaskStatus() == TaskProcess.graded || assignedTask.getTaskStatus() == TaskProcess.grading) {
      mainVC.contextPut("String_Node_Str","String_Node_Str");
      setGrading(ureq);
    }
  }
 else   if (assignedTask == null || assignedTask.getTaskStatus() == TaskProcess.graded || assignedTask.getTaskStatus() == TaskProcess.grading) {
    mainVC.contextPut("String_Node_Str","String_Node_Str");
    setGrading(ureq);
  }
  return assignedTask;
}

Fixed version (ground truth):
@Override protected Task stepGrading(UserRequest ureq,Task assignedTask){
  assignedTask=super.stepGrading(ureq,assignedTask);
  if (businessGroupTask) {
    String userLog=courseEnv.getAuditManager().getUserNodeLog(gtaNode,getIdentity());
    if (StringHelper.containsNonWhitespace(userLog)) {
      mainVC.contextPut("String_Node_Str",userLog);
    }
 else {
      mainVC.contextRemove("String_Node_Str");
    }
  }
  String infoTextUser=config.getStringValue(MSCourseNode.CONFIG_KEY_INFOTEXT_USER);
  if (StringHelper.containsNonWhitespace(infoTextUser)) {
    mainVC.contextPut("String_Node_Str",StringHelper.xssScan(infoTextUser));
  }
  if (config.getBooleanSafe(GTACourseNode.GTASK_ASSIGNMENT) || config.getBooleanSafe(GTACourseNode.GTASK_SUBMIT) || config.getBooleanSafe(GTACourseNode.GTASK_REVIEW_AND_CORRECTION)|| config.getBooleanSafe(GTACourseNode.GTASK_REVISION_PERIOD)|| config.getBooleanSafe(GTACourseNode.GTASK_GRADING)) {
    if (assignedTask == null || assignedTask.getTaskStatus() == TaskProcess.assignment || assignedTask.getTaskStatus() == TaskProcess.submit || assignedTask.getTaskStatus() == TaskProcess.review || assignedTask.getTaskStatus() == TaskProcess.correction || assignedTask.getTaskStatus() == TaskProcess.revision || assignedTask.getTaskStatus() == TaskProcess.solution) {
      mainVC.contextPut("String_Node_Str","String_Node_Str");
    }
 else     if (assignedTask.getTaskStatus() == TaskProcess.graded || assignedTask.getTaskStatus() == TaskProcess.grading) {
      mainVC.contextPut("String_Node_Str","String_Node_Str");
      setGrading(ureq);
    }
  }
 else   if (assignedTask == null || assignedTask.getTaskStatus() == TaskProcess.graded || assignedTask.getTaskStatus() == TaskProcess.grading) {
    mainVC.contextPut("String_Node_Str","String_Node_Str");
    setGrading(ureq);
  }
  return assignedTask;
}