Editor toolbar overlaps Save buttons

I’ve been having an issue with the 13.* series (at least 13.6 and 13.8) where the CKEditor toolbar on the bottom covers over at least part of the “Save” controls strip at the bottom of the page (when in WYSIWYG mode and scrolled to the bottom).

I attach an image of what this looks like. This is happening in current versions of Chrome and Firefox.

Capture

Do I have some issue with a CSS sheet somewhere? I haven’t customized any of the built-in ones. Is there an obvious fix? Thanks in advance.
-Alan