Yes. They've had a big problem with people who want cannabis to be sold out of state using a chain of people purportedly home growing as a cover for illicit cultivation, essentially.
I was a big fan of home growing to start with, based on the theory that you shouldn't push people into a market for something that they could do for themselves. I think it turns out that the regulatory problems around home growing were harder than I thought they would be. Therefore, the Washington approach now looks more sound than the Colorado approach.