Well for those interested in some helpful info, and not just here to pimp Linux Mint or tell us about their PC running XP, the guys at NeoWin seemed to have narrowed it down a little.
“For whatever it’s worth, we’ve actually recreated this problem with our own Kindles. In our testing using USB 3.0 ports seems to be the issue, with USB 2.0 ports seemingly not being affected. We can also confirm that rebooting the PC with the Kindle still plugged in allows users to then access their Amazon devices.”
Thank You, VDK!!
FWIW, my own Win10 machines haven't had the opportunity to get "Kindled", and won't, but I appreciate your info nonetheless for my users' sake.