Ticked checkboxed show as unticked
I have a PDF form which I filled in using Evince, then edited in LibreOffice Draw (because Evince doesn't interpret one of the fields correctly) and saved to PDF again. When I open the result in Evince, the checkboxes which are ticked show as blank. If I open the same file in Draw, they show as ticked. I've filled in a number of copies of this form and this is the first time the checkboxes aren't showing up correctly. I can share the original file privately (via email).