Stamped #Keywords are misaligned or not visible

image-2020-11-06-10-26-16-042.jpg (99.1 KB)
C:\Users\mth1\Desktop\2022-05-24 15_25_56-[P20-59458] Custom Stamping_ Stamped #Keywords are image-2021-04-27-17-11-30-091.png (8.4 KB)
CustomStamping (1).zip (6.2 KB)
E1B722080995_A.pdf (60.6 KB)
We have aspose.pdf-20.12.jar, and I have attached our code it is in the zip file.
I have attached files with examples.

@MariLouise

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.