I've also hit this issue today and I completely ignored the 'Skipping group hiera with no hook script None' log since it showed up as a warning but it in the end it was the cause for the hung stack create. +1 for making this condition an error.
I've also hit this issue today and I completely ignored the 'Skipping group hiera with no hook script None' log since it showed up as a warning but it in the end it was the cause for the hung stack create. +1 for making this condition an error.