Skimmed through some of the other advice but didn't read all.

First I have never had light leaks cause hermies. Light leaks aren't stress to the plant. Light leaks can just cause problems with flowering. Some strains seem to demand total darkness - and seems to be more related to those strains meant to just be grown indoors. So I don't think the tiny lights on your power strips/timers are going to be the problem.

A big topping of the plant like you gave it, is probably what caused the stress and then causing it to hermie.

I also prefer a warmer room during lights on, but don't think that's your issue.

As far as switching from veg to flower light times, a lot of people recommend doing at least a 24hour dark period before flipping to 12/12. I've tried it several times and didn't seem to make a difference in how quickly flowering starts nor did it increase bud size