Roz tells Frasier how happy she is that her mother finally opened up to her and they could now have a heart-to-heart conversation, yet in Season 1 Frasier overhears Ross having an intimate conversation with her mother on the phone about details in her sex life.
When Frasier says "A Hail Mary" he looks over to Roz. The shot cuts to Roz even though Frasier is still speaking, except that Frasier's reflection can be seen and it doesn't match the dialogue.