This really isn't true. He had one amazing month when they switched back to normal baseballs from the tacky baseball. Outside of that month he had a sub .800 OPS in AA in every single month.
April - .712
May - .739
June - .714
July - 1.164
August - .718
September - .792 OPS
As Jack states in the article, Chourio crushes mistakes and struggles when pitchers execute their pitches. With AA changing from a tacky ball with extra grip to a normal baseball, I've always speculated that pitchers were struggling to execute in that first month leading to Chourio seeing far more mistake pitches.