When using a quality transformer, it attaches a quality icon to the player while input or output power is enabled. When both settings are disabled, the quality icon gets "dropped" on the floor and stays there until you enable them again.

Yeah... Due to the way this mod unfortunately has to be coded, there are invisible entities that are 'attached' to the player. I haven't checked the mod api recently, but last I checked there was not a way to hide the quality icon. The reason the icon stays in one place is that when both input and output are toggled off, the code doesn't do the check to move the PT entities to the player/owner of those invisible entities, and as such they just stay in the location they were last left. This was the most efficient way to handle this in order to save on UPS when not in use.