Communication means sending a message and ensuring that it is received and understood. But then, what could "over-communication" possibly mean?
Sam can write 100 emails and still not be understood because he writes poorly. Of course, he can claim that he "sent constant reminders," but all he did was send out a barrage of data containing negligible information. (reminds me of our educational system)
On the other hand, John expects to be understood without speaking, like the "grumpy experts" we've met often. Both data and information are absent.
What we need to do instead is coordinate. For example, at the start of the sprint, the information is about the stories that need to go out. During development, information is exchanged to resolve any blockers. Toward the end of the sprint, information is exchanged to bring the release together. In each phase, the information exchanged was different, which is coordination. Whereas "over-communication" usually means repeating the same data while expecting different results.