What Worked –
Uninstalling and Re-installing Kindle App
What Did Not Work –
1. Closing app and re-opening app
2. Turning tablet off and then back on again
3. Removing and re-downloading book that Kindle is having problems with
4. Settings –> Applications –> Kindle App –> Force Stop
(You might try these first though.)
Postscript – April 13, 2020, around 11 PM Denver time, Kindle started malfunctioning. It made me re-login repeatedly, and this post got a number of hits right then. Whatever was going on, it seemed to be something from Amazon’s end. It may be that just ignoring it till they fix their problem will take care of things too.