verisium ore being smelted with no-one assigned

Noticed this twice, I was trying to save my verisium ore for upgrades, checked the smelter. Bars are being created with no-one assigned to it. Only way to stop it is to un-assign all smelters.

There is a tooltip that explains that is how that works in-game. The only time the ore is ever needed for upgrades.. after that you'll never have to worry about assigning smelters again. They probably should have left out the raw ore upgrades.. but it is what it is.. get the upgrades, assign everyone back, ignore them rest of the league.