Let's assume prediction markets are efficient and you didn't already possess any relevant information that you weren't trading on beforehand. Then you should treat the market odds as a prior and your die roll as evidence, in exactly the way you always do Bayesian updates. In this case, that means it looks like that gives you a posterior probability of 5/14 each for the die being weighted in favor of 3 or 6, and 1/14 for each of the other possibilities. Contrary to what other commenters were saying, it doesn't matter what information led to the market odds under these assumptions.