Both these augments and GM cultural armors have built in chance-of-success caps.
GM chest pieces, for example, are capped at 60%. That means no matter how high your skill or how strong your trophy, you can still expect to fail 40% of the time on that combine.
I don't know where the cap is for augments; I am guessing it is at about 70%. If that is right, you would expect to fail 30% of the time. The chances of failing 4 times in a row would be 0.81 % -- about 8 times in a thousand. That's not common, certainly; but it means that if 1000 tradeskillers all do 4 augment combines in a row, we would expect 8 of them to fail all four times.
It turns out that you are one of those unlucky 8, this go round.
Sorry. I hate failing on combines with rare stuff, too.