I'm curious about this thread too, so please keep us updated

I'm definitely leaning towards that your plants aren't getting enough moisture, and I say that because I 100% understand your southern window environment because that's what I have now too; I just moved in August. My plants were drying out too quickly in their new windowsill, so I started watering more frequently (2x a week) because with the southern sun, its strong enough even in the winter when most people would ease up on watering. I definitely see increased growth and "'activity" when I keep the watering up. I should also note that I grow in S&H also, and I have all catts. I keep watering because if I slowed down on it, they would go into dormancy and/or cook to death.