Well, so much for taking the hands-off approach. Winter is coming and the heater has been on, which is drying out the air more. Temperature is the same in the grow room, but humidity has plunged to 23%. Gave the plants a thorough watering with nutrients last week. Today and the rest of the week, I'm going to treat them to just plain water until next week.
UPDATE: Humidity definitely the culprit. Placed a small humidifier by the plants on Wednesday, and they sprang right back. All is going well now. Seed description says flowering phase of 11 Weeks. Should expect to begin harvesting around Dec. 20th (4 weeks from now).