I am testing Aspose.Diagram .NET 18.5.0 and have found an issue with the colors of the background when I save to PDF. What is grey/brownish in the lower left is green in the resulting PDF file.
IncorrectBackground.zip (613.7 KB)
We managed to replicate the problem of incorrect background color. It has been logged under the ticket ID DIAGRAMNET-51473 in our bug tracking system. We have linked your post to this ticket and will keep you informed regarding any available updates.
The issues you have found earlier (filed as DIAGRAMNET-51473) have been fixed in Aspose.Diagram for .NET 19.4.