That's probably because the cloned Lex Luthor from the finale was created from DNA from BEFORE "Requiem."
It wouldn't make sense for him to have memories of those events.
It's just like how Zod and his cloned army's last memories are from when their DNA was taken.
It also wouldn't make sense for the Lex from Requiem to have been a clone. They confirmed onscreen that his injuries were from the Fortress collapse and he was after the suit as his lifeline to recovery.