I was looking at https://wikitech.wikimedia.org/w/index.php?title=Talk:Deployments/Train_vs_backport&mobileaction=toggle_view_mobile on my phone while logged out.
Tapping on any of the discussion headers doesn't take me to the discussion. No JavaScript error is logged, but I noticed tapping on the header just appends more and more open-block classes to the div
Tapping on the headers does work fine as a logged-in user.