I have just updated from High Sierra to Mojave and discovered that Preview displays PDF files in an extremely blurry way (before the update it was fine). My screen is 27'' Thunderbolt display.
The link used above is https://arxiv.org/pdf/1005.1585.pdf?view=FitH p. 2. Both browsers were opened side-by-side in a fullscreen mode.
I think that fortunately the update has not affected Chrome (also Acrobat Reader works fine for me). But apparently the update has affected something used in Preview (and other apps, such as Skim), presumably PDFKit as mentioned here.
On the Internet I have read that this issue might be related to antialiasing, but none of the recipes solve the issue. Is there any other solution, or shall I hope for a fix in the next update?