Kirov Park Meeting. What triggers the explosion to be visible or not?

I’m working on my series right now for the Kirov Park Meeting episode. My method is that I snipe the gangster from the radio tower, and let the general run to his car which I’ve put the bomb on. Sometimes, after sniping the first target, and staying up on the radio tower, once the general reaches his car (which we can’t see, since the whole thing is obscured by a building) there will be a huge fiery orange cloud light up the sky, which happens right when the blue “objective status updated” notification comes up. It’s a beautiful scene.

However, it seems that half the time, you hear the explosion without seeing the orange cloud.

I haven’t been able to pin point what causes it. Whether it’s starting with a fresh load vs on a “restart mission”, or whether it’s the way you sit or stand on the radio tower, or something like that.

Does anyone know what I’m talking about, or have any ideas? I want to find out how to assure that the explosion shows up, so I can replicate those conditions for my video.

Something similar to this is whether or not the limo driver honks the horn right as he drives by. He sometimes does, sometimes doesn’t.