Towers are not spawning properly and Demolitionist Tonn seems to be adverse to blowing up the invisible one.
Does this happen every time? It’s an issue I’ve never seen, so I don’t think the story step as a while is “broken”.
I’ll bug the prop artists about the towers, they’re playing their “destruct” animation correctly but are, indeed, invisible to start. I didn’t have any issues with having Tonn blow up the towers, him planting his bombs is independant of what the tower looks like. Make sure you kill any enemies in the area and approach the quest star (where the bottom of the tower would normally be.)