Or it could just be that they feel stiffer.
As much as I wanted to like the NYXLs when they came out a few years ago, I found that for me at least they felt at least 1 gauge stiffer than one would expect. They were too-pricey for me anyway, so too bad, 'cause I felt that if I'd gone down a size I might've achieved a similar feel to what I was used to, and of course, IMHO at least, they sounded very-good. Plenty of sparkle that hung around for weeks of use.
I've recommended them to a couple of peeps since, but always with the caveat that they try 1 gauge down from what they normally use in order to bring things back-to-normal.
So yeah, could it just be that the CM strings are stiffer than regular ones at equivalent gauges?