Problem with yellow leaves on Haze, Advice needed please

I have a Haze autoflower with leaves that are dying. Maybe a nute burn? This is only my second grow so I'm still learning.

The plant is around 7 weeks old, about halfway through flowering. It is in Promix soil and has been getting FoxFarm nutes (Grow Big & Big Bloom during veg, and Big Bloom & Tiger Bloom for flowering). The leaves started showing yellowish spots on the fan leaves about 10 days ago and have become worse every day. The fan leaves now have brown spots and some of the smaller leaves are getting yellow spots. The last 2 waterings have been just water no nutes hoping it would recover but I've seen no improvement.

I have a Pakistan Ryder autoflower that is the same age, same nutes but shows no signs of yellowing.

Any help would be greatly appreciated.

Do you know what your PH is doing?

I don't have a way to test PH right now, need to buy more strips.

All the other plants are doing fine so I was thinking maybe that strain of Haze is more nutrient sensitive than others. Could be wrong though.

I'm just hoping to keep it alive for another month till its ready to harvest. The buds look good so far and I'd like to keep it that way.

*BUMP* did you find a solution to the problem?