Safari Version 13.1.2 (15609.3.5.1.3) MacOS 10.15.6 (19G73

See https://codesandbox.io/s/pagedjs-safari-infinite-rendering-issue-nu0mf

Notice line-height: 15px in styles.css. It should render fine, in console you should see "preview done 2 pages".

Now change line-height to 30px and reload. The previewer will go into "infinite rendering loop". You will not see the "preview done" console log, and if you inspect the html structure, you will see that the number of pages rendered just keeps growing without stopping.

Now change line-height to 40px and reload. You will see "preview done 1 page", and a warning that says "Unable to layout item".

Interestingly enough, if you remove the outer div.book from the template, the "infinite rendering loop" issue goes away, but the 40px-issue remains.

As I understand, officially Safari is not supported by pagedjs at the moment. But maybe it will help to debug in the future.