...

It might take a lawyer of someone experienced in intellectual property rights to say for sure. But here is what I suspect: Qora devs sign the Azure contract. After several months of development under the Azure veil, MS can claim that the "new" Qora is significantly different from the "old" Qora, which was MIT licensed. And as such, they now have legal dominion over the "new" Qora.

If a company takes something that exists in the wild, like a fork, say, something very common, and enhances it with some new design that significantly improves on the old design, then they can apply for protection (a copyright or patent) for their enhancements to the original, public design.

I admit that I am not an expert in these matters. I am simply trying to contribute a healthy dose of suspicion to this opportunity.