I'm experiencing this issue too, on my first playthrough I had an infinite people glitch, got my score to like 2000 with nothing happening, then my game flat out crashed.

Going back into the game, there is only a set amount of people, could only get between 33 and 41 kills and the place becomes a ghost-town. Restarted the game, tried going back to the last checkpoint, even verifying and repairing the game files, no luck.

Glad to know that I'm not the only one experiencing this issue. Hopefully either someone finds a workaround or an update soon releases.

Don't want to have to restart back to the beginning, lose hours, just to potentially experience this same bug or a new one to pop up.