Discoloration on some leaves

Hi there and thank you in advance for your assistance.

I'm new to this forum and am looking for assistance is diagnosing our problem.

We are in the 4th week of flowering; plant is roughly 3 feet tall and 2 feet wide. We set ph on water to 6.3 to 6.5 and for every gallon of water we use 3/4 tsp of Micro, then 3/8 tsp of Grow, followed by 1 1/8 tsp of Bloom.

We are experiencing some leaves looking like this photo. We suspect it is a nutrient or ph issue, but need your opinions.

Thank youAttachment 283660