Preview stamp not always "in front"

E1B5806555_A_preview.pdf (101.1 KB)
attachment8-E1B5000521_A_merge_preview.pdf (242.3 KB)
CustomStamping (1).zip (6.2 KB)
We have problem with stamping, text or part of text disappers on created PDF files, I have attached a couple of examples
We use aspose.pdf-20.12.jar and I have attached a zip file with our customized code


Can you please share a simple code snippet which we can run to reproduce the same issue in our environment. There are undefined methods and classes in the .zip file that you shared. Also, please make sure to test the scenario with the latest version of the API before sharing the code snippet.