When AutoZone had the sale years back, I grabbed a bunch. The jugs I have used do have the reddish tint. I think it is normal and due to the additives. What is interesting as well is that compared to other Mobil 1 oils, the TDT has a distinct and unique smell to it. The other oils smell, like... oil, the TDT has a stronger, more pungent smell. A different form of zinc being used? It has to be one of the additives.
The Delvac 1 ESP 5W-40 CJ-4 version was similar, we were using that in our tractors and truck. The Delvav 1 has changed a little going to CK-4, the color doesn't seem quite as dark.