If I change the password of user pi (rpi 3b, NOOBS, Raspbian Jessie), it takes affect only until shutting down or logging off. After shutting down or logging off, the new password is no longer current.
I was using SSH and VNC for a couple hours before failing to be able to connect any longer. When I was local again, I was able to change the password and get VNC working again, but only until the next reboot or login.
What would cause this problem?