Deficiency or ph?

This happened overnight after I watered yesterday. Is this due to low ph? Is it a deficiency? My grow was going so smooth until this week! Ph going in is 6.3, ph coming out is 5.7. I just made another post on how to get ph up but want to make sure it’s not something else.

Strain: White Widow CBD Autoflower by ILGM
Method: Soil (Fox Farm Ocean)
Vessels: 3 gal fabric pots
PH: Last watering was 6.3. Runoff was 5.7
PPM: 60 ppm going in. Runoff 1650
Light: Marshydro 1000. 14 inches above canopy
Temps: 72-74 day / 64-66 night
Humidity: 40-48
Ventilation system: Yes, 4 inch
Co2: No
Nutrients: GH FloraNova

Excess nitrogen (if not other nutrients as well.) 1650 PPM is too high for an auto and the nitrogen effects are seen in the dark green, waxy leaves.

Thank you! Should I flush the plants now or just not add any more nutrients in future waterings? They only have about 3 weeks left so I planned to start final flushing in about a week.