This is very likely the same issue. The lazy loading seems to be enabled only for images which aren't (or shouldn't be) immediately visible for the reader (i.e. offscreen) upon the page loading. Sections are usually collapsed on the mobile site (although they seem to be uncollapsed on larger screens?), which would explain this. Removing the display: block CSS from the class in Firefox's inspector seems to solve it.

I agree. It's definitely broken on Hebrew Wikipedia in the example you gave me. I'm going a little crazy though... I've neen copying and pasting the source code from that page to other pages and can only replicate it on Hebrew

See:

• https://fr.m.wikipedia.org/wiki/Utilisateur:Jdlrobson/sandbox or Arabic
• https://ar.m.wikipedia.org/wiki/%D9%85%D8%B3%D8%AA%D8%AE%D8%AF%D9%85:Jdlrobson/sandbox
• https://en.m.wikipedia.beta.wmflabs.org/wiki/User:Jdlrobson/pi2?u
• https://he.m.wikipedia.org/wiki/%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9:Jdlrobson/sandbox2

This rule is applied on the beta cluster

li .lazy-image-placeholder, span .lazy-image-placeholder {
    display: inline;
}

but this doesn't apply on Hebrew Wikipedia because the HTML markup produced by the wikitext for all those pages is different from the example page you gave me despite me using the same source! o_O

Is there a different Math extension or an older version of it being used on Hebrew Wikipedia from other wikis?

(oh and whoops I didn't mean to resolve this before! Not sure what happened there)

This does appear to be working on production - https://he.m.wikipedia.org/wiki/%D7%9E%D7%A9%D7%AA%D7%9E%D7%A9:Jdlrobson/sandbox2