Game mechanic, smelters inquiry

https://imgur.com/a/bdZHBPq

I went offline and came back to find 0 verisium ores while assigned 0 smelters. Was saving for town upgrades later on.

Is it intended for other smelters that is not assigned to verisium to work on any available ores if theirs run out?

Same, came back to zero ore.

Yes, it works that way with the miners as well. It says it on the information tab, but maybe could be more obvious and/or have a way to lock them on one material type.

Hope they add an option or remove this feature, I can't really do anything if I'm asleep.