Bug: Weird corner case with cards that use both titanium and iron (e.g. Space Elevator)

[Siobhan]

Situation: Holding 2 iron, 4 titanium and 18 cash. Play Space Elevator (27 / space & build tags). Since I can't afford the card without spending resources, the game presents the UI for doing that, with it set by default to 2 iron and 2 titanium. I want to use the iron for something else, so I increase the titanum to 4. The iron contribution cannot be lowered below 2, however, even though it is no longer necessary.

[DengDeng]

Same. Happened 4 times in my 6 games. As you always want to save one steel to use this card right away. So frustrating. My top concern of the game so far.