Safari Devtools logs error when running in a cross-origin iframe, rendering <label>Email</label>

[mb21]

Do you want to request a feature or report a bug?
bug

What is the current behavior?

This seems very similar to #14002

Put the following code in a react component:

<label>Email</label>
<input type="text" />

Put the whole app in a cross-origin iframe (as is already the case in CodePen).

Safari emits the following error in the dev console on render, and every time when you focus the text field:

Blocked a frame with origin "https://s.codepen.io" from accessing a frame with origin "https://codepen.io". Protocols, domains, and ports must match.

Interestingly, another label text works fine. Only <label>Email</label> triggers the error.

Demo: https://codepen.io/anon/pen/MRRbLz

What is the expected behavior?
No error is logged in the console.

Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?

• Safari Version 12.1 (14607.1.40.1.4) on macOS 10.14.4
• react and react-dom 16.8.6

[mb21]

Uh, this actually happens even without react. It's a pure Safari bug, sorry for the noise.