Thanks so much for your effort — I really appreciate it. I tracked the problem to the HTML in WordPress; the culprit was this line:
<figure><img src="https://s.w.org/images/core/emoji/17.0.2/svg/2728.svg" alt="✨"></figure>s.
I rewrote the code and everything looks fixed now.
Thanks for taking the time to check. I tried another browser and had the same problem, so the issue is probably in some script somewhere in WordPress. The question is just where.
