Tutorials bug

So i was fooling around in the tutorial and found a crucial bug.

When Bob asks you to upgrade the tavern from tier 2 to tier 3 , you can instead buy minions. At that time, the upgrade costs 6 gold and you only have 7 gold.

If you buy ANY minion, you can not use buffs, you can not sell minions and you get stuck with the sign asking you to upgrade the tavern.

It could be very confusing for the very new players who would either accidentally buy minions, or decide to not follow orders.