I've seen it in females to which I've given a calcium+D3 supplement from mating until laying, so I think it's something beyond just a calcium deficiency.
In any case, the eggs will still be viable. The shells are more fragile in that area and as they develop and swell, those patches can be more prone to rupturing. Having said that, I've had an entire clutch look similar and result in some of the fattest most reliable eater hatchlings that I've ever seen! Plus is pretty cool to be able to see the embryos developing.
Just be careful with them and try not to move them around - hopefully all will be well.