E.g. in PDFs created or edited with "Master PDF Editor" http://code-industry.net/pdfeditor.php, checkboxes are sometimes displayed correctly, but do not print as expected. Instead of a tick mark, a number is printed, probably because Okular inserts the wrong font. Reproducible: Always Steps to Reproduce: 1. Tick PDF checkbox form. 2. Print. Actual Results: A number is printed in the box. Expected Results: A checkmark (tick, cross, whatever was specified in the PDF) should have been printed. See attached examples.
Created attachment 86709 [details] A pdf with a fillable form.
Created attachment 86710 [details] Print-to-PDF result with checkbox checked.
Well, the 4 is the checmark :D
The actual number depends on the type of checkmark that has been set in the pdf. It may also be an 8 in the case of a tick (✔) instead of a cross (✘), if I remember my experiments correctly.
This is my workaround for the problem: Checkboxes are printed correctly if somewhere in the PDF-document a review (F6) emphasis (yellow pencil) is made. Transparancy can be set to 1%, so this mark is not printed actually.
*** Bug 376300 has been marked as a duplicate of this bug. ***
This is still happening, with PDFs generated using Scribus. Link to a relevant poppler bug: https://gitlab.freedesktop.org/poppler/poppler/-/issues/541