We have GroupDocs Conversion running on a .NET Core 3.1 service that is driven by a queue, so multiple conversions can run simultaneously. This results in the following exception:
GroupDocs.Conversion.Exceptions.GroupDocsConversionException: 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 GroupDocs.Conversion.Converter.Convert(SaveDocumentStreamForFileType document, ConvertedDocumentStream documentCompleted, ConvertOptionsProvider convertOptionsProvider)
at GroupDocs.Conversion.Converter.Convert(SaveDocumentStream document, ConvertedDocumentStream documentCompleted, ConvertOptionsProvider convertOptionsProvider)
at GroupDocs.Conversion.Converter.Convert(SaveDocumentStream document, ConvertOptions convertOptions)
Seems like a concurrency issue on a static or shared component somewhere.
This is similar to an issue in Aspose.Words for .NET: Execute Multiple Mail Merge Jobs on Word DOC Document in Multi-Threaded Environment using C# .NET Core 3.1 - Free Support Forum - aspose.com that was apparently fixed in the 20.7 update of that package.
Might there be a 20.7 update of GroupDocs.Conversion that also fixes this problem?