SUMMARY I attached the PDF file. On Evince and Xournalpp I can correctly display it. SOFTWARE/OS VERSIONS Linux: ArchLinux
can't attach PDF file because too big, you can find it here https://mega.nz/file/TQ1ynZ4S#Wo-lp8x4QTxlUv8W1SnjeqQp_0F8xNC6COhqWNCHKoA
Yes, our rendering of stamps is not super good, and this being a custom stamp is a bit broken.