In my experience a plant hermies because of some sort of stressor. You're plants look pretty nice and loved. The Calyx splitting open from the seeds makes me think they are about 4-5 weeks old from being pollinated. You mentioned you changed light cycles, is that around the same timeline ? Are most of the seeds pretty well developed ?
Maybe a naughty neighbor chucking pollen around ? I thought about nailing my neighbor with some pollen if he keeps parking his oil leaking shit box in front of my house. But then, I wouldn't want to give him free good feminzed seeds/genetics.