There are some references to it in this thread but I couldn't find any posts discussing NH partner award availability within this thread (no, I didn't read all 500 messages, but I did read ~the last 100).

Did this change recently? Based on https://www.flyertalk.com/forum/35733681-post1272.html, it seems like most UA has more visibility than other *A partners, but historically I remember UA availability matching NH's own availability, which seems to be no longer true. When did this change occur, or am I mis-remembering how it used to be?