If you were to add text to the Instructions field that will appear in a Post, for example:
Use for embeds not supported by oEmbed. i.e. an <iframe> might appear in here.
The “<iframe>” tag will render the Post edit screen useless – all the fields get thrown out, due to what it thinks is an unclosed tag.
I just use html entities when adding instructions, to prevent the tags from rendering.
Thank you. For sure there’s workarounds, but I spent a fair bit of time trying to figure out why my post screens were broken, so a permanent solution would be nice, as others might experience a similar issue.