Sped up particle effects in Coal Tower main building

Alionis

When inside the Coal Tower main building, there is a particle effect of water droplets dripping from the piping that can be seen on the ceiling of the lower floor. Every 20 seconds or so, the animation will suddenly speed up so that instead of the occasional drop every second or so, it just showers down the droplets as if it's raining inside the building.

I had this on Steam and it occurs every time I play that map. You can see the "rain" in the screenshot I took.