I missed your 2nd paragraph. I regret it’s not much help to me as i have never used the Anova recipes although i have assisted cooks who have in this forum.
The usual description for that beef is “velvet” translated from Mandarin. It’s not likely you dredged your meat in cornstarch to get that effect, which is what Chinese cooks do, so the mouth feel puzzle remains.
Until there’s more evidence i’m still thinking you might have bought a low quality piece of meat. It happens.