I had mentioned this to some of you in the past, but I found something unique with youtube. All of the SBS videos I've loaded in the past are interpolated by my new 4K Benq TK800 projector as 1080x24hz frame-packed. I have no understanding of why this happens as the projector is supposed to accept only 1080x60i or 1080x50i SBS. Well there is one SBS video that doesn't respond this way, it shows up as 1080x60p SBS 3D. The other SBS videos are automatically switched, but this video I had to force into SBS 3D. Long story short, I then realized that I had sent this as a test video of loading a dual (SBS) L/R full frame 1080x30p video to youtube a couple years ago. It shows up as a normal compressed SBS when you look at it in 2D, but it's not. Somehow youtube loaded it differently. Here's a link:
I created this file out of Edius for those who might want to experiment creating a similar file.

Bob- I have a number of YT videos like that. The clue is in the meta data. If I create a YT video in SBS half rendered with Vegas Pro v 11 it will not have the meta data in the rendered file that says- "I'm a stereoscopic 3D SBS half file, not a 2D file." But if I render it with an editor like Edius 7.53, the meta data is present. Also, I can force the Edius to be a SBS half render by not rendering it to SBS half as a 3D render but edit the SBS with a replica of left and right eye images, then use the layouter to make it look like a 3D SBS layout and render as a 2D file. I uploaded some of these too. I did this when I wanted to prevent YT from setting the project to anaglyph, forcing the viewer into seeing it as a 3D program on a 3D TV.