Is this a bug?
lol, No. When you choose to get a blessing or curse, it's random what get's picked. It's more likely that you don't get a blessing or curse, but they are both independent of each other. So it'll do a random roll to see if you get a blessing, and then the same for the curse. But getting both and having them cancel each other out is about a 2% chance (I think). Basically it's a 1/16 chance to get those for each.