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.
Clients need flexibility. Developers need a repeatable workflow that doesn’t have a steep learning curve. See how digital marketing agency Noiza found both with Advanced Custom Fields in our latest case study.https://t.co/BxQAy6COJt