1. I made video project and wanted to use it in new videos as template. I give name for this video is "1.veg". Added some dark video to timeline. Added levels FX with gamma to my video. When I render this - video have bad quality and it's ok. But I don't have blinking artefacts.
2. I create video project "2.veg" and add to timeline my first template ("1.veg"). Vegas creates a proxy. Now I can see blinking artefacts on preview or after rendering "2.veg".
About artefacts. It's rise artefacts from frame 1 to frame 14, and again and again. I take screenshots in prepared dark video with max gamma for showing that effect. Picture 1 - frame 1. Picture 2 - 14 frame.
Maybe I need make templates in some other way? I don't want to render "1.veg" in advance.