Yes, go with watching pH, just check it isn't usually an issue in your stage.

But the humidity change can do all sorts of  bad things.

The plant is used to getting a certain amount of moisture from the air. Lacking the water it takes it from the roots concentrating salts in the roots and can elevate the soil ppm. other things like drying out sooner than schedule, can cause the plant to behave poorly. Get the humidity on her or switch to 12/12 and give her a flush. 

Others here might have a better take. These are things I would do. Some work, some don't.  So take it for what it is.

Given the right conditions these plants grow themselves.😊👍