Parenthood (1989)

Continuity mistake: During the family dinner, the level of the wine in all the characters' glasses changes from one shot to the next.

Marilyn Buckman: Cool is adorable. Adorable! Why didn't you write us when you had a son?
Larry Buckman: I didn't know myself until a couple of months ago. You see, a few years ago, I was living in Vegas with this girl. Showgirl. She was in that show 'Elvis On Ice'. Anyhow, we drifted apart, as people do in these complicated times, and then a couple of months ago, she shows up with Cool and tells me "You watch him. I shot someone. I have to leave the country " That's a parent?

Trivia: On the promotional movie poster, a frazzled Steve Martin is shown holding 2 children upside down by their ankles. On the set, sometimes the children would get unruly, so as a joke, Steve Martin once grabbed 2 of the unruly children and actually held them upside down by their ankles. Director Ron Howard saw this and decided it would make a funny promotional picture, so that's where he got the idea for it.

Question: Since Helen is one of the 4 adult Buckman children, and had been previously married to Julie and Garry's dad, why is Julie's last name also Buckman? I could see Helen going back to her maiden name, that's not uncommon but it would be unusual to have a teenager (in the late 80's) who had her mother's name rather than her father's. Or was this a plot hole that was created so that they could create the conflict of the photographs scene?