Convert ePub to PDF fails to render some pages

[rfog]

Converting attached ePub into PDF (attached as well) fails to render pages 25 to 56, showing only some words and equations. It seems because that chapter contains some math equations.

Calibre 5.14 under macOS Big Sur 11.2.3

Calibre options:

* Look and Feel
** Fonts: FCaslon 30 ITC
** Embed all fonts in document enabled
** Styling: "p {line-height: 0.9}"

* PDF Output:
** Custom size: 12x15
** Serif Font family FCaslon 30 ITC (font is attached into zip)
** Default font size: 16 px
** Margins all set t0 20.0 pt

Custom header template:
<header style="justify-content: center;font-size:x-small"><div class="even_page">_AUTHOR_</div><div class="odd_page"><i>_TITLE_</i></div></header>

Custom footer template:
<footer style="justify-content: center;font-size:x-small"><div></div><script>document.currentScript.parentNode.querySelector("div").innerHTML = ""+ _PAGENUM_ +" of " + _TOTAL_PAGES_ +" (" + parseInt(_PAGENUM_*100/_TOTAL_PAGES_) + "%) / " +_TOP_LEVEL_SECTION_PAGENUM_ + " of " + _TOP_LEVEL_SECTION_PAGES_ + " ("+ parseInt(_TOP_LEVEL_SECTION_PAGENUM_*100/_TOP_LEVEL_SECTION_PAGES_) +"%)"</script></footer>

I've converted more than 100 books with those options without any problem, only this book has issues.

[Kovid Goyal (kovid)]

Converts fine for me with those settings apart from the font, see attached. Cant test the font since I dont have it and you only attached one of the faces for the font.

[Kovid Goyal (kovid)]

Oh and the equations are just images, so wont cause any issues