Hello stuntz0rZ, the best suggestion is to use a straight cable (HDMI to HDMI), but if this is not possible, an active converter may work better than a passive one.
This article lists tested cables and adapters: Intel® NUC Boards and Kits — Tested peripherals
Sorry for the late reply.
I no longer have the problem. Something has fixed the issue. Either a bios or graphics driver update... I haven't seen any red lines since i started this thread. I'm using both video outputs now. Keep up the good work