Heading alignment changed in Editor

All of a sudden my H1 H2 H3 are not following theme margins as they have been when editing pages earlier.

I am using storefront them and have been working on with a child theme for a couple of weeks and today the editor is showing headings with odd placement in the editor only – browsing the site the headings are in correct position.

Headings are now forced full width with different left margins depending on header size. Adding a H1 forces all the way to the left 100%. H2 has more left margin but still not aligned, H3 has different left margin than the others and P aligns where it should.

I did run troubleshoot mode and see it is OK in default themes but both storefront and storefront child themes show the headers with incorrect alignment.

Tried searching for similar issues for hours with no luck. Has there been any other reports of this for storefront or it just me?

See image linked here:
Screen Shot

Thanks for any ideas.