Long time lurker here. I was playing on xmage the other day and I have a Trinisphere in play. My opponent has Academy Rector in play, no free mana and Cabal Therapy in the graveyard. He is able to flash back Cabal Therapy and sacrifice the Rector without paying any mana. Cabal Therapy did not resolve (ie, he neither named a card nor looked at my hand), but the damage was done: he got to search for some monster enchantment and put it into play. I don't recall what the xmage message window reported during this.

Is this a bug or the correct sequence of actions?