Some tables/forms in EPUB don't display correctly
Here's the Sumatra v3.4.14237 64bit:

And the same table in my web-browser epub reader:
I can provide the .epub file if you need, but it's over 40mb, maybe not in git-hub.
This is a known issue that in general ebook tables with columns are not well defined/supported and is thus a duplicate of several historic issues. The core issue is MuPDF rendering of epub.
Too sad to known about this. Hope it wound be fixed soon.
Thanks for the information btw.
=> MuPDF issue : https://bugs.ghostscript.com/show_bug.cgi?id=700013 No activity since 2019-08-22, status is still in UNCONFIRMED 😔