After treatment dozer valve operation

[RSCTRANS]

Here is my question and then an explanation of the scenario. When does the dozer valve release fuel into the exhaust system? I know it operates during a regen . However, after I serviced the dozer valve, I had forgotten to tighten up the two boats mounting the valve to the pipe. They were not super loose but loose enough that when I started driving the truck with an empty trailer, fuel was leaking onto the outside of the exhaust pipes causing white smoke. I quickly realized that I had forgotten to tighten up the bolts, and when I did the problem went away. My question is does the dozer valve release fuel constantly? I do not think it was doing a regen when I started driving it as I thought the lights on my dash would show me that.