Yes but that's assuming this isn't a GG auto.......could a mistake have been made? Possibly. But unless the seed company gave you a thai landrace or something by mistake......
It could be a pure sativa, and your greenhouse is preventing good sun from getting through, but that's really not what greenhouses do. Unless you're in a very low sun climate, like trying to grow Panama Red in Northern Canada.
The super light flowers, the high leaf-to-calyx ratio......is it possible that some sort of artificial light outside is hitting your greenhouse at night? Street lights, your own flood lights, anything? I'm still leaning towards light pollution throwing the plant into that veg/flower twilight zone.