Yeah, "weird" isn't what I meant to describe the tie's behavior, it makes perfect sense that being more slippery would cause it to slip. A double four-in-hand does hold a bit better than a single, but the thinner silk/lining tends to produce a bit of a gun-barrel knot for me when using the D4IH.
I'll play around with it a bit more and try another knot, but it should come as no surprise that, as a StyFo member, I get a bit OCD about ties that have come away from the collar to the point that *gasp* you can see the top button.
I would definitely use the knot that Mark Cho uses. I have been using that for more of my thinner ties and it works nicely. I had no idea that was the knot he used lol.