SDDM Crash on Scroll

Release: Kubuntu 17.10.1
kwin: 5.12.4
sddm: 0.14.0
kernel: Linux 4.13.0-38-generic x86_64

If I scroll quickly or extensively, my session crashes to a black screen resetting to the login dialog for SDDM. I am unsure if this is KWin, Plasma, or SDDM, but I have tested the following scenarios:

* I noticed before a crash that I repeatedly see this in Xorg.0.log on repeated scrolling within a window, regardless of it being a Logitech speed scroll or touchpad scrolling:
    [Xi] Too many valuators reported for device 'Virtual core pointer'. Ignoring event.
    Previous to any crash, 2 of these appear: [dix] EventToCore: Not implemented yet
* Wayland and Xorg show the same behavior when I scroll--crashing after I scroll.
* This occurs whether I scroll in Firefox 58.0.1, Kate, Dolphin noting the lack of specific graphical toolkits relating to this issue.
* If Plasma was the culprit I am supposing it would just restart plasma-desktop rather that lead me back to the login dialog.
* Intel HD 530 graphics (Nvidia modules blacklisted for bbswitch to load on demand), with SNA acceleration. UXA acceleration also showed the same behavior after restarting with change to /etc/X11/xorg.conf.d/21-intel.conf

Hoping to fix session crashing on Plasma/SDDM/KWin when scrolling.