After upgrade, every phone call displays an ad?
I forgot I had added recording software.  Going into safemode definitely established that it was not Android itself.  Then the question was how to find the app.   I don't have a great answer, but scanning through all the apps showed me that I had added one, and denying it privileges fixed the problem.

As a side-note, Android desperately needs a way to identify a page or notification and see who is responsible for it.