By checking the edit history, there was a wikitext added to the <ref></ref> tag, which may have a format error that caused this issue.
https://en.wikipedia.org/w/index.php?title=2023_Israel%E2%80%93Hamas_war&diff=prev&oldid=1181763009

This edit broke it for Parsoid. It moved the </onlinclude> from *outside* the transclusion to *inside* the transclusion. So, Parsoid looked at the content within <onlyinclude> ... </onlyinclude> and found an unclosed transclusion and rendered it as text.

In the core parser, since it basically strips the onlyinclude tags no matter how it is nested, it is none the wiser.

Parsoid could be *smarter* about this, but this is a case of GIGO in my opinion and not something we are likely to priortize fixing any time soon (unless these kinds of errors are more common and we need to gracefully recover).

I think this task is also causing https://en.wikipedia.org/wiki/Wikipedia:Arbitration/Requests/Case to display with the raw template text in Parsoid, and it is very much not GIGO.