I've tried a fully composed ad that is static, I've tried simply the logo being moved around on the canvas. It does not seem to work with Chrome(surprising), Edge or Internet Explorer. I've not tested it with Firefox yet. The cache for Google Web Designer has already been cleared without any noticeable benefit, and while I have not reinstalled Google Web Designer this is a fresh install already.
My Operating System is Windows 10.
I think I've laid out any of the most basic of answers to simple questions. I can only imagine it works fine for other people, so hopefully a fix can be figured out.