850ci overheating while sitting... Steaming+ pouring out water gauge reads normal???

I left my 1996 850ci running with the wife sitting in the car while I went in for 5 minutes to pickup Tacos... 65 Degree Cool night, AC was off.



There was steam from the overflow and water poured out when I loosened the cap. The gauge read dead center normal. The Engine Fan was turning but not the electric fan...



Experts??

850ci overheating while sitting... Steaming+ pouring out water gauge reads normal???