Looks to me like calcium deficiency to be honest. Make sure your giving your plant a healthy boost of MagNifiCal or some other Calcium/nitrogen supplement in their next feed. If you fed them with nutrients last time add some Calcium/nitrogen supplements to the water and that’s it. Those leaves probably won’t recover from
The damage so when It grows more leaves out you can trim out the dead /damaged ones. (This is all assuming your ph pen and all that is working correctly and has been calibrated)