Yeah, that's definitely left over shed. It will eventually wear off, my rescue boy had never had any
UVB light and his temps were far too low, and when I got him he looked so dull and just dark brown, like he was almost one solid, dark, dull color because he was stunted and as a result of not growing he wasn't shedding either. At all. So after about a month of proper
UVB light and temps, and proper diet, he started to grow and shed. But it's been very tough for him to get all the shed off an area at one time, he's got retained shed everywhere. I was really concerned about his tail last month because he had shed the tip and the very top, but the middle didn't/wouldn't shed. It looked ready to go for over a month, but it just wouldn't. I gave him a short 10 minute warmer than average
bath every other day (he had come to me severely impacted and with severe MBD, so he needed the warm soaks to poop too, he still does as the muscles from his lower back and below are still extremely weak) and after almost 2 months he finally shed his tail completely just last week...
His body has fully shed twice now, and his tail is starting again, so hopefully this time it will go more easily, but as long as the retained shed that is going around his entire tail diameter isn't cutting off the circulation to the rest of his tail distal to the shed, he'll be fine and it will eventually come off. Just make sure his temps are correct, and I recommend giving him short soaks in warm water every other day, for no longer than 10 minutes. I make his water the same temp as my other beardies, then add just a little bit more hot water so that the temperature is about 5 degrees warmer than usual. He seems to like this a lot, he gets very comfortable looking and perks up, probably because he poops, lol. I tend to actually
bath him every day just so he has a chance to poop if need be, but you don't need to do that unless your guy really loves the
bath and drinks out of it.
That yellow shed will eventually come off, just keep an eye on the rest of his tail below the yellow area, make sure it stays colorful, warm, and soft, and there are no signs of severe blackness, stiffness, etc.