I think the consoles still send out the battery values, even if , there is not a sensor sending data. I'm not sure on this, but there is a bit of sense on doing this. For instance if you have a sensor go off line because of a low battery situation, the battery status may hang around to give you that clue why, if it was a low battery situation.
Again, this is my conjecture. I do know that it hangs around on Ecowitt.net for like a week, even if you have removed the sensor. I'm just making a guess that the console is still sending it. It could , of course just be the web site. I never did look at wsview to see what happens, I spend most of my time checking Ecowitt.net
maybe someone else knows