Hi, I'm having the same problem as this user.
iframe seems to disable the navigation on desktop and removes the hamburger menu on mobile. I've tried it both as a code block and and embed block and there isn't any change. No code injection. I really only use CSS to customize text so it shouldn't be affecting this.
Affected website link.
Normal website link (for reference).
Code for the iFrame:
<!DOCTYPE html>
<html style="height: 100%; margin: 0; border: 0">
<body style="height: 100%; margin: 0; border: 0">
<iframe
src="https://hub.catalogit.app/iframe/110"
style="border: none; width: 100%; height: 750px; box-sizing: border-box" />
</body>
</html>