I've used a green light in the grow room for years without incident with a few different strains, but I've also seen plants seed themselves too. Whether or not the green light work done during the "dark hours" was responsible for the adverse effects remains debateable. Personally, I don't even take the chance anymore. Unless you can afford the possibility of these type of problems I'd stay away from them. George Van Patten wrote a book about growing indoors and it had a small section on this subject saying that phototropism was most affected by what color spectrum the most? You guessed it.....green light.
The question still remains though, is phototropism during the dark period a bad thing? Being that it's probably not natural probably not, but the industry greenhouse standard for "lights out" is supposedly zero lumens. What that actually means is, you could actually still be able to read a newspaper in the room during lights out and the plants not be affected. Personally, I'm done rolling the dice. Take your chances if you want though. *2 cents*