iirc my first two squaddie specialists had a hack of 45 with not created equal on. I've had a few soldiers with high hack scores (which is generally meh), but those don't seem to carry over to when they are specialists (e.g. 11 and -2 both get promoted to 45).
I'll keep an eye on this and make sure it's not user error, but figured I'd post in case others have noticed it. My second specialist was switched classes via console, so that could very well have impacted things there (unrolled the not created equal stats or something).