Hi Allan,
Details follow
What is the NUC model?
D34010WYK
Operating System version? if 32 or 64 bit.
Windows 7 x64 Ultimate
Video driver version?
10.18.10.3345
Also, the graphics report generated within graphics properties
Report in attached file
XBMC version 12.3
Symptoms are macroblocking/screen flashes on all .mkv files encoded with VC1 when using dxva2, it appears that this is a well known issue over on the xbmc.org forums as well.
http://forum.xbmc.org/showthread.php?tid=178421
Regards Phil