Testing files attached, please compare the displays of MuPDF, Acrobat Pro and Foxit Reader, MuPDF seems has an render issue with the dotted-lines.
Created attachment 7288 [details] testing file
FYI: Disabling "Enhance thin lines" in Adobe Reader results in the same rendering as MuPDF's.
Could you please define "Enhance thin lines" as the default with MuPDF, like other PDF viewers/readers, thanks.
*** This bug has been marked as a duplicate of bug 691930 ***