The quest prompt to intercept another factions attempt to attack the forge of souls should not have an option to "intercept later", if the other faction is going to win this turn. I thought I would have time to recruit 4 units to my army on a legendary playthrough, so I clicked the "later" option, and lost the game. It wasn't communicated clearly anywhere that this was the last chance to intercept before complete campaign loss.
Horrible user experience. I sinked tens of hours into that terrible grindy legendary campaign for an achievement.
Please consider just removing the "intercept later" option, or communicating more clearly that the other faction *will* win once you end your turn.