Definitely a glitch, and a very bad one too, game-breaking. I played through a second time and the scene triggered immediately as soon as I walked around the corner, right after the scene where the barrels are first delivered. The first time I played through, it simply never happened, for absolutely no reason, and I talked to people over and over and over in vain looking for something I'd missed. There wasn't anything.
And having the conversation with Kid Tannen doesn't have any effect on it. It triggered for me before I ever spoke to him, though I did talk to Emmett and Edna before going in to the soup kitchen.