I have observed the issue shared by you and request you to please try using latest Aspose.CAD for ,NET 20.3 on your end. In case you still feel it an issue then please share the working sample code along with source files with us.
I am using latest version of Aspose.CAD (20.3).
As you have size limit for uploaded files can you please send me which email I should use to provide download link as I cannot publish download link which is available for all. Of course, you can also provide location where I can upload project and test file (or increase size limit to 20Mb).
Please check the following image. You can click on my name Icon and will find a Message option. Please use that to send me the requested information privately. Please notify me here once you have shared so that I may verify.
I have worked with the sample project shared and have been able to observe the issue.An issue with ID CADNET-1058 has been created in our issue tracking system to investigate and resolve the issue. This thread has been linked with the issue so that you may be notified once the issue will be fixed.