It's beautiful, right? So what is it?
I'm just going to quote Schuyler Camman, who was a Professor of Oriental Studies at the University of Pennsylvania before his death in 1991. He was an anthropologist and art historian and he did some ground-breaking work on Chinese symbolism including magic squares and the meaning of cloud collars. I'm planning to tell you more about the symbolism of cloud collars in his amazing article in another post.
Anyway, Camman says,
And let me tell you, once you see the motif, it is everywhere in Central Asian art.
So sometime in the 17th c somebody was tasked with fixing it and chose to add a cotton backing for stability and then used green embroidery to completely cover the shattered crimson silk. So it worked, technically. The embroidery was saved and the object continues to exist instead of being completely destroyed. But, the choice of a lower contrast replacement for the crimson silk is pretty clearly a choice made by someone who did not share the same aesthetics and design sensibility as the Persian royal workshop that originally produced it. (There were also some attempts to repair damage to the embroidery, but the use of silver gilt thread instead of the original gold makes the repairs pretty evident.)