Hello,
Check the user-scalable attribute again.
1) We did not disable any plugins because we were working on child theme files only.
2) We did not touch anything except child theme header.php file. That’s all. And changes in that file could not affect headings. I checked your h1 (SWEET BABY ROOM) and it’s less than 20 characters, that’s why you see that warning I suppose.
Regards