Sleeping monitor rewakes and displays broken version of lock page

[Simon Lyall]

I am running a dual monitor desktop. After I lock the system the screens go dark and then sleep. However at some point (minutes, hours?) one of the screens re-awakes and displays a broken version of the lock screen (Ubuntu logo in center, version towards the bottom). The stays displayed indefinitely until I login.

I'm running Ubuntu 16.10 (installed, not an upgrade) on a desktop. Monitors are both Samsung SyncMasters 2443's and video card is "NVIDIA Corporation GF108 [GeForce GT 430]". The Primary (left) is plugged in via DVI while secondary (right) is plugged in via VGA. Resolution is 1920x1200 on both.

The "bad" screen is distorted from the normal lock screen in that:
(a) It is not centered
(b) It is a darker blue than my actual screen background (that I see right after locking)
(c) There is a white grid of dots
(d) the is a black line across the screen level with the Ubuntu version.

See attach photo.

Expected behavior: Screen stays turned off.

I previously had 16.04 on this machine, did not have this problem.

Description: Ubuntu 16.10
Release: 16.10

gnome-screensaver:
  Installed: 3.6.1-7ubuntu5
  Candidate: 3.6.1-7ubuntu5
  Version table:
 *** 3.6.1-7ubuntu5 500
        500 http://nz.archive.ubuntu.com/ubuntu yakkety/main amd64 Packages
        100 /var/lib/dpkg/status

[Simon Lyall (simon-darkmere)]

Followup photo from this morning. Right hand side is the "problem" scrren that was running when I came to the computer.

Left hand screen was initially off but woke up to the login/unlock screen when I pressed a key.

Note colors on left are completely different (and match my normal settings) and correctly centered etc.