There but for the Grace of Grace - S2-E21
Continuity mistake: When Will and Grace are sitting at the dining table discussing how much like Sharon and Joseph they are, the napkins on the table change shape and move around a bit, and one ends up with a plate underneath it just before Will picks it up.
Continuity mistake: The art show is supposed to take place at the Zelman gallery and inside there is a sign that says that, but the establishing shot shows that the name is the Phyllis Kind gallery.
Plot hole: Will and Jack are out on the patio talking about the first time they met at a party (implying in college) and how Jack convinced Will to come out, but in S1E6 Jack talks about Will's favorite book in elementary school. I am re-watching the show now, and I am sure they have a conversation about hanging out as kids. Makes no sense. Time 1 is season 1 and time 2 is for Season 2. (00:06:33 - 00:13:10)
Suggested correction: I just re-watched the scene you referenced from Season 1. Jack is talking to Grace and is throwing out random Will trivia. He never said he knew Will in elementary school, just that he knows what Will's favorite book was when he was in elementary school. There is no plot hole with this statement.
