It looks like the instructions field is not being escaped for < and > characters and is rendering anything between them as HTML. Most tags are automatically closed by the browser, but <iframe> specifically breaks it because it busts out the whole HTML #document.
The tags render as HTML in all fields I tested including children in a repeater.

My specific use case was giving instructions on how to paste an iframe into the field.
If you want to include HTML in your instructions for a field you need to use <
and >
when writing your instructions.
Actually I was just instructing the user to do something with an <iframe> code block, so trying to write “<iframe>” – can you escape the < >?
Sorry, hard to put in this site as well. Remove the sapces from this
The last I know you could use & lt;
and & gt;
in the message field to show html.