Working as it should.....your IP is set by DHCP from your ISP and is loosely based on the MAC address of your router. Even with that, your address is not fixed (unless you pay for a fixed IP from your provider) and can change just by rebooting the router.
I guess it's ok. It's just weird. It seems to be only effecting Asus router as I have some other older routers and they all had 24.x IP range. May be it has something to do with IPv6 and Comcast and how Comcast distributes IPs.