Video controls messed up since 16.04

I run Xubuntu 16.04 LTS on three different machines - my home desktop, my home laptop and my work desktop. I use xscreenaver on all three machines for my screensaver. Each one has a different video controller, and from 10.10 - 14.04, these all worked perfectly.

As of 16.04 and the latest updates from early last week, 1) the slideshow does not work, and 2) the screen will not shut down unless I physically power it down.

This began happening after I upgraded (both desktops) or installed (laptop) Xubuntu 16.04.1 LTS (since then updated to the L&G).

I did reinstall the nvidia 340 driver on my laptop, as that is the most recent driver with support for that screen, and the screen still does not turn off unless I close the lid for some extended length of time like overnight. However, the slideshow seems to work with the nvidia driver.

I have checked into whether Jamie changed anything in the xscreensaver that might have cause this. Other than his abrasive style, there does not appear to be any issue there.

Given that this occurs on multiple machine with different hardware and the commonality is the OS (and screensaver, which worked fine on 14.04), I suspect there is a problem with the video drivers used in 16.04 as opposed to 14.04 and earlier.

Relevant details:

Home desktop - custom built, i7-4790 CPU, ASRock z97 Pro4 m/b, onboard Xeon E3 1200 v3 video controller running the (Ubuntu-supplied) Intel i915 video driver. I don't recall for sure, but I believe that the video driver for 14.04 was different.

Home laptop - HP8710W, Core 2 Duo CPU, NVIDIA Quadro FX 1600M video controller using the nvidia 340 driver (note: with the nouveau driver, the slideshow does not work).

Work desktop - HP x640 with Xeon E5-2620, 32GB RAM, nvidia GM107GL [Quadro K2200] video card running nvidia 367 driver on two monitors.

I was going to report this as a bug, but I figured I should ask here first.