This particular swap is definitely in error. Agave scabra is a legitimate large species of Agave, not resembling the much smaller low-growing fleshy Manfredas at all. A quick Google search of images of Agave scabra and images of Manfreda species will show you it is completely out of place in the genus Manfreda.

I am only familiar with the handful of Manfreda species that occur in Texas. If there is a species of Manfreda known as Manfreda scabra that exists elsewhere, then a taxonomic mess was just made that will take some work to correct.