Fuji replaced my camera. It can now record 4K/24fps video on a single battery without overheating. A total of 54 minutes on one battery. I now get similar performance reported in Zed ProMedia's video.
As Zed ProMedia suggested, I pulled screen away from the camera body.
Meanwhile, I got about 25 min of continuos recording at 4K/30fps with screen in normal position (not pulled away from body) before camera overheated. And about 35 minutes with screen pulled away from camera body.
So to get maximum 4K recording follow Zed ProMedia's settings: 4K/24fps with screen pulled away from camera body.
Compliments to Fuji's fast turn around in getting my issue resolved. Took about 4 business days with priority overnight shipping.