"You were being told that the rush tickets were sold out, not that all tickets were."
Actually the original poster makes it sound like the matinee was sold out. If only rush tickets were sold out, the box office would've said "no rush" and leave it at that. But they followed up by saying the matinee was sold out.
In any case, I agree with AEA. The block of tickets sent to TKTS are linked to a different computer system than what is sold at the box office, so it may have been sold out on the Cort's end.
"We like to snark around here. Sometimes we actually talk about theater...but we try not to let that get in our way." - dramamama611