Thanks for the tip Mike! I did a "Check for Updates" when the problem happened to see if there was a fix, but it told me that 10.1.7 is the newest version available. I've manually downloaded 10.6.9, and the problem seems to have gone away.
I don't know how I ended up on an older version of Evernote. My computer did a reboot due to Windows updates, and there was a message saying my Evernote had been updated when I logged back in, and it had me at version 10.1.7.
Thanks again for the help.