From OTRS: https://ticket.wikimedia.org/otrs/index.pl?Action=AgentTicketZoom;TicketID=11611813
Inconsistently-but-regularly reproducible on both an iPhone X and a (second edition) iPhone SE. Scroll through article, and TOC is sometimes not updated.
"best reproduce it with longer articles with a lot of sections. Donald trump is a good example and what I’ll do is I’ll start to scroll mid-article...check it once and then sporadically check the TOC position a bit more shifting around.
While it’s inconsistent in terms of sometimes it scales with the scroll and sometimes it doesn’t, it’s extremely consistent with the inconsistency itself, meaning if I pull up trump’s article, I may not get every section to work or not work, I’m still almost guaranteed to encounter at least a few sections not working within the bulk"
Consistent repro: "Actually if you open “Donald trump” and immediately scroll mid-article, my first attempt to dive into the TOC always sticks to the top rather than jumps down with you. So lmk if you can’t repro but that is a 100% repro for me over 12 slightly unique consecutive tries. "