Hi. Yes, here is a scenario. USAir.com had availability for this Thursday using low economy miles on this: lga-clt-sfo. I went to ANA to see if there were more options with *A partners. ANA showed no economy options for any airline. It didn't even show the flight # that USAir showed as an option for business or first even though on USAir all 3 were available.

BTW, On ANA I did search each leg separately. I don't believe any leg was being operated by a smaller airline either. I checked. No luck. I logged out and tried it later in the day and I still had the same problem. I worked on a different trip and the same thing happened. USAir had more availability than ANA. I didn't jot down those details though.

I am going to try and duplicate these results again later today.