Unable to "Close" a draft

[Michael Wolfe]

I'm attempting to resolve a problem with a client's server, DC 7.13.3, where when you click the "Close" button on a draft, the editor never closes, and an error appears next to the Save and Close buttons that says "Can't save changes".  I've checked the confluence logs, synchrony logs, and catalina logs on both nodes, but neither yield any errors.  Synchrony is "Running" on both, and Synchrony restarts haven't fixed the problem.

Has anyone experienced and fixed this kind of issue before?