When you bluff low you lose if you get called on it. When I have played Bluff in the past you would win if you bluffed low - and only lose if you were bluffing higher than you have.

Is this version of Bluff supposed to work differently - or is that an error?

I don't think. The program is the same for 2 versions: you lose if you announced something different that your cards, higher or lower

Aha! Thank you.