I'll assume that means there was a problem with 1 out of the 12 cats, or in other words a 5% change this food is going to cause a health issue. Personally I find risking my cat to 1 to 12 chance unacceptable, and that is assuming those were all male cats.
I don't want to open a can of worms on...
STAY AWAY from Kirkland Dry Cat food. I fed my cats this food and my male cat developed a urethral obstruction. That is cause by the food. From my time working for a vet during high school, I knew and saw this caused by low quality cat food. $1,500 at the vet later, I will never feed my cat this...