Everything sounds good, wasn't sure if maybe fans were blowing directly on the plants, that can do some weird things. Low humidity too, from what I've read, I'm going through that myself now but symptoms are different. I'm not a fan of 24/7 lighting myself, but if that works for you great, a lot of people do it with no ill effects. It's just not my thing. I believe in lights out, letting the plants rest and do their work. But that's only my opinion. I'm sure if you've done it for so long with no problems that's definitely not the issue. Hopefully you'll be back on track in no time. Best of luck to you buddy, keep us posted. Happy New Year!