I knew from my previous research that paṭola was the precursor of Cambodian ikat. But had assumed that brocade and ikat came to Cambodia from different sources, because ikat appears later.
But, after Ashavali brocade strips began to be exported from Gujarat, and then Ashavali brocade sashes, Ashavali developed into saris with paṭola in the central field. Brocade and ikat may, eventually, have come to Cambodia together, in the form of these Ashavali saris.
This would solve a mystery. Indian paṭola (ikat) is plain weave. But Cambodian ikat is twill weave. The brocade in Ashavali saris is in the border and end piece (the paloo), and is twill weave. The ikat is in the central field, and is plain weave. Cambodian ikat weavers may have simply liked the twill weave better – the reverse side of the ikat would be a slightly different color than the right side, making the piece more marketable (below; the bats on the top are the right side of the ikat, and the bats below are the reverse side). (I have often bought Cambodian ikat for the reverse side, because I liked it better than the right side.)
But this just raises another question. Ashavali brocade today is twill weave (below left - look for the diagonal slant in the weave, most visible at the bottom). But chorabab, which evolved from Ashavali brocade, is plain weave (below right - no diagonal slant).
Why is chorabab not twill weave? The most likely explanation is that, when Ashavali first reached Angkor early in the 12th century, it was plain weave. We will probably never know.