We render reports to PDF with ReportProcessor.RenderReport, and several renders run in parallel in the same process (background jobs). Occasionally the report items show this error inside the generated PDF instead of their values: "An error has occurred while processing TextBox 'textBox8': Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct."

Exception and stack trace:

System.InvalidOperationException: Operations that change non-concurrent collections must have exclusive access. A concurrent update was performed on this collection and corrupted its state. The collection's state is no longer correct.
   at Telerik.Reporting.Processing.Data.GenericObjectDataDescriptor.TryGetValueInternal(String name, Object data, Object& value)
   at Telerik.Reporting.Processing.Data.DataMember.TryGetValueOverride(String name, Object& value)
   at Telerik.Reporting.Processing.Data.DataObjectBase.TryGetValue(String name, Object& value)
   at Telerik.Reporting.Processing.Expressions.FieldsNodeEval.Eval(Object data, Object context)
   at Telerik.Reporting.Expressions.FunctionNodeEval.Eval(Object row, Object context)
   at Telerik.Reporting.Processing.TextBox.ProcessItem()
   at Telerik.Reporting.Processing.ReportItemBase.ProcessElement()
   at Telerik.Reporting.Processing.ProcessingElement.Process(IDataMember dataContext)