In September, I tried to use all $50 in one transaction at T-Rex and we could not do it.
We used all fifty in June of this year with no issue. I had also emailed Landry's prior to the meal to make sure this was allowed. The reply said yes.
We were NOT able to use our AP discount with Landry's Select on a later visit. It was one or the other. We did not have any rewards to redeem on that meal. We simply could not earn more when using the discount.