DAVE PROWSE GEORGE LUCAS FEUD EXPLAINED
Lucasfilm wished to keep the “I am your father” moment under wraps
ahead of and upon the sequel’s initial release for obvious reasons.
However, Den of Geek notes that Dave teased the reveal to the press
beforehand, saying: “Father can’t kill son, son can’t kill father, so
they live again to star in Star Wars IV.”
The Sound of Her Voice (Season 6 - Episode 25) https://memory-alpha.fandom.com/wiki/The_Sound_of_Her_Voice_(episode)
Without watching the episode again I believe the final time is a scene in Engineering where O'Brien and Kasidy are in Engineering. O'Brien is working on the com line and he's chatting with Kasidy about the Defiant having civilians aboard then ...