Reported at https://en.wikipedia.org/wiki/Wikipedia:Village_pump_(technical)#Reply_script_not_loading_properly?.
For few days now I've been having trouble with the reply button: after I reply to one comment, the reply button will disappear and I have to reload the page to see it. Quite annoying when I want to leave multiple comments on the same page. This happens in English and Polish Wikipedia, in differne browsers (Chrome and Edge), and in two accounts I checked (I've an authorized alt).