No, they are generally broken. On android when timer goes to 0 enemies spawn at map entrance and stay still there. On web version when timer goes to 0 enemies spawn and go to your base. However balcony don't shoot, traps don't work, doors don't block them. They just enter gate room and stay there. Defenders in gate room do nothing just stay and stare creeply on enemies.From what i saw, it bugs out when the invasion reaches 0 sec. All countdowns freeze, for daily, for buys, for hearts. Everything. That is probably the bug that blocks people.