No second monitor - Fedora23 KDE spin

[CS DBA]

All;

I'm running Fedora 23, KDE spin. I've fully updated my system. several 
updated back I could plug in a second monitor, go to system settings --> 
display and click on the second monitor to 'enable' it

However a few updates back this functionality stopped working. Now I 
plug in the HDMI cable, go to system settings --> Display and it only 
show the laptop screen.

I've installed the Cinnamon desktop and it seems to work flawlessly per 
auto-adding the second monitor as soon as I plug the HDMI cable in.  I 
suspect this confirms that it's a KDE issue and not a Kernel issue, but 
I'm not 100% sure.


Any thoughts on debugging this?

I'm running on a Lenovo X1 Carbon 3rd gen, lspci listing below, thanks 
in advance


$ lspci
00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 
09)
00:02.0 VGA compatible controller: Intel Corporation Broadwell-U 
Integrated Graphics (rev 09)
00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller 
(rev 09)
00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI 
Controller (rev 03)
00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI 
Controller #1 (rev 03)
00:19.0 Ethernet controller: Intel Corporation Ethernet Connection (3) 
I218-LM (rev 03)
00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition 
Audio Controller (rev 03)
00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root 
Port #2 (rev e3)
00:1c.1 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root 
Port #3 (rev e3)
00:1c.5 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root 
Port #6 (rev e3)
00:1d.0 USB controller: Intel Corporation Wildcat Point-LP USB EHCI 
Controller (rev 03)
00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller 
(rev 03)
00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03)
00:1f.6 Signal processing controller: Intel Corporation Wildcat Point-LP 
Thermal Management Controller (rev 03)
04:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59)
0a:00.0 SATA controller: Samsung Electronics Co Ltd Device a801 (rev 01)