* Playing as Triss in a 4-player game with 3 AIs

* I had 2 Blue Lead tokens and 2 Red Lead tokens when I drew Foul Fate "Bushwhacked!"

* I chose to spend 2 Lead tokens rather than fight a battle

* Game automatically spent 2 Blue Lead tokens instead of giving me the choice between 2 Blue Lead tokens and 2 Red Lead tokens

Shouldn't I have been given the choice?

No, the game choose randomly what leads to take.

Then it's a bug. Per the rules:

"If an effect instructs the hero to spend (or receive) leads
without specifying a color, the hero may spend (or receive)
any color lead."