Soft close toilet seat issue
The Kohler Cimarron toilet comes with a Reveal Quiet-Close with Grip-Tight Bumpers Seat. You can swap that for any elongated seat, though obviously with a new toilet you wouldn't normally want to do that - except if it came with a regular seat and you wanted a soft-close seat, which this already is.

Supposedly, it has "Unique Grip-Tight bumpers hold the seat firmly in place and prevent shifting." That would seem to imply that it would do the exact opposite of what it is doing for you. Since it is brand new, I suggest contacting Kohler directly.