High Mileage and Synthetic Blend

In short, yes. This could have started because the synthetic does tend to act like a thinner liquid. In my opinion, if you don't start it on synthetic by 100k, don't bother. Conventional "dino" oil tends to run at slightly higher pressure, and that stresses the seals and gaskets in the engine just a little more, sometimes causing micro leaks that synthetic can get through, but not dino oil. In short, your problem might go away if you switch back to dino oil, or it might be here to stay, but it's not a big deal as long as the oil consumption doesn't get bad.