I freely admit to being slightly impatient and to having scanned the puzzle hints and spoilers just to get an idea of what to expect... and as a result, I think I may have found either a glitch in puzzle 12 or a mistake in the spoiler for it.

I'm running 2 villages.

In the first one, I got level 2 in culture last (of the level 2's) and the sewing hut popped right up.

In the second one, I got level 2 culture 4th and still had medicine and science to go... and no sewing hut.

So is this a game glitch, or a spoiler mistype?

I don't know which guide you read, but the guide in this forum's guide section correctly states both requirements. The guide that's linked from virtualvillagers.com hasn't been updated and needs to be replaced - that should happen soon.

I read the one you linked on virtualvillagers.com. Good to know it's just a misprint and not a glitch. Thanks