I have recently noticed that the dashboard embedding now has a strange left padding.
This seems to be a problem from a change in the CSS.
You can clearly see them in the embedded playground as well.
This also causes the embedded dashboard to show a bottom scroll bar and the content is hidden under the right scroll bar.
The screen below shows the problem at hand, from what I can see, it is caused by the left and right being set for some weird reason.
Take a look at Optimize a dashboard for phones and create a support ticket for assistance if necessary.