Stuck on billboard

[playable]

I'm playing CQ2 with my kids and we're stuck.

We are on the downtown delivery quest. We talked to the Grubin Elder, who wants to buy the Crestwailer's club. We talked to the Crestwailer, who says he won't sell his business while it's so damaged by the billboard from the Trowbog Elder's club.

I was doing something else for a bit, so I don't know if my kids talked to the Trowbog Elder after that. But definitely other things were done in the game. Then they felt stuck and we went to talk with the Trowbog Elder. All he will do is talk about all the cars going by his billboard. It doesn't matter if we talk as Jefferson, or honk as the Clown, or anything else, from what we can tell.

We went back around and talked to the earlier quest giver at the Elite Speakeasy, the Grubin Elder, the Crestwailer club owner, and the Trowbog Elder again. We tried honking the horn over and over. We tried quitting the game and restarting. The only thing the Trowbog Elder will talk about is all the cars passing by his billboard (or, immediately after the clown horn, he'll comment on his laughing).

Is there anything else we could try? We really want to finish the game -- but they will feel really frustrated if we have to start over to do it.

[DelTab]

I had this game free on epic game yesterday and I met the same glitch.
I know it's a long time you asked the question, but I may help people to get unstuck by sharing my experience:
I don't know if restarting the game is necessary, but I did it, then I went to the couple next to the swimming pool and talked to the man (not diplomacy, simple talk)
It started the quest (which was not previously present in the quest book) and I'm unstuck now.