Created attachment 348445 [details]
Yahoo Mail (mobile) compose button bug
To reproduce this bug, use Safari Technology Preview in responsive design mode, or an iOS 12 (beta) device.
Navigate to https://mail.yahoo.com
You must use a mobile user agent or you'll be redirected to "desktop" mail.
Note a floating, oblong-shaped button in the lower right corner with a pencil icon. It is used to begin composing a new email.
The button does not have its clip-path applied correctly. To compare, try viewing the same application with an older version of Safari, or with Chrome.
See attachment for further clarification.
We can close this. Found a workaround, or rather, what changed.
Now the clip path respects padding of the container. Seeing this, I can just remove padding from the container and it should render correctly for all clients.