Water draining into floor drain from inside the drain
You could have a p-trap primer. I found one of these devices connected to the floor drain in my old kitchen/laundry room, when we were remodeling. This device, similar to below, periodically "flushes" the drain and refills it to ensure you have a seal in the drain so that sewer gases do not come back up the p-trap into the house. The device can be hidden in a wall therefore not easy to find, and then a tube of some sort to the drain. Mine was inside the wall, connected to the washing machine cold water line, similar to the second photo. When we remodeled and moved the laundry to the garage, the floor drain was filled in and the p-trap primer was removed from the wall and the line capped.

How often the device worked I am not sure, or how it decided to run, I am not sure.