Nations
How does Sun Tzu's extra action work, and when do advisor bonuses take effect?
The designer quoted the FAQ on Sun Tzu's timing and confirmed the solo roll, and the rulebook's card notes agree.
Sun Tzu gives two actions in place of your first turn of a round, but only if you already had him at the start of that turn. Buying him as your first action gives no extra turn. In solo, the Shadow rolls once, after both actions. Other advisor bonuses take effect at once when acquired.