The Ken wrote:
I have a fireXC pro with the same issue - the tyre is at fault in my case but I rode it for months before being annoyed enough to do anything about it. It is either a manufacturing defect probably caused by a tyre being removed from the mould wrongly/too early or something to do with the way the tyre was stored in the shop, although I think this is less likely.
I have an Mud Pro that does the same.
If you think it's the tyre at fault, use your guarantee and the barcode on the inside of the tyre.