In fact, there seem to be multiple issues with printing annotations (at least text highlighting).
This is about Evince 3.36.7 and Okular 20.08.2.
1. If a highlighting annotation is created in Evince, it is visible when the file is opened with Evince, Okular, or Xournal++, but it disappears on printing to PDF file from any of these programs, and it disappears on exporting to PDF from Xournal++. (I believe it also disappears on actual printing.)
2. If a highlighting annotation is created in Okular, it is visible in Evince, Okular, and Xournal++, but when printing to PDF from Evince or Xournal++, the first highlighting is ok, but all the others hide the text that is supposed to be highlighted.
In fact, there seem to be multiple issues with printing annotations (at least text highlighting).
This is about Evince 3.36.7 and Okular 20.08.2.
1. If a highlighting annotation is created in Evince, it is visible when the file is opened with Evince, Okular, or Xournal++, but it disappears on printing to PDF file from any of these programs, and it disappears on exporting to PDF from Xournal++. (I believe it also disappears on actual printing.)
2. If a highlighting annotation is created in Okular, it is visible in Evince, Okular, and Xournal++, but when printing to PDF from Evince or Xournal++, the first highlighting is ok, but all the others hide the text that is supposed to be highlighted.