If the soil is too moist, the rootball can easily fall apart, so letting it dry before transplant is good idea. If her progression is getting worse, transplant asap, but be all set-up and ready to transplant, before taking them out of the pots. (wet rootballs fall apart)

If you slip the rootball out of the pot, what color are the roots...? Should be very white to slightly dingy white.
What color are the roots growing tips...? Should be very white.

It could be that it's not uptaking water...but this will continue until you rectify the problem. (lockout) Don't overnute, and let the soil dry before adding more moisture. (water or nutes) This may mean you'll need to adjust your schedule, by tweaking quantity of water you add, or waiting longer between waterings.

Something to take into considderation: the plants in front of the fan, and directly under the lights will lose moisture through evaporation faster than the ones tucked into a stagnant corner. Don't water all plants, just because plant A is ready. Gotta check them all, at every watering. (It'll get to the point that you can look at 'em and tell)

A day or two before nutrient day, back-off the waterings, so they are more than ready to be fed and watered. Don't keep the soil wet.