Hi,
So, unfortunately that padding change between themes is a bug that we’ll need to fix.
When setting the chrome to transparent we also remove the outer border, and the padding with it, with the expectation that you would set custom padding on your container with custom background if you also have a new border too. The reason being that if we left the border in place (with its rounded corners) it would be harder to manage background bleed of the container while compensating for the default chrome.
Ben