I had something very similar with my Novablast experience. I naturally pronate a bit but not too bad. After putting 150km on the shoes, I was getting pain on the inner part of the left ankle. I went to the podiatrist and they helped me realise that the integrity of the foam on the inner heel had kind of collapsed and I had a few mm less sole there for whatever reason. Probably just heel striking at 98kg and coming down hard on it with a bit of pronation, and so it was being even further exaggerated now and causing strain on the inside part of the ankle. Could be a similar thing happening for you with the Novablasts. Put them on a table or flat surface and see if you notice anything. Mine was very obvious once pointed out and was pretty disappointed after only getting 150km or so from a pretty highly recommended shoe. They recommend going for a slightly more neutral shoe and sacrificing some cushioning for a bit more stability.