Once the food hits 165 it's killed all germs that may have started to grow. So the 4 hour window doesn't start until the food hits 140 F - actually 135 now per USDA. Now if there was some bacteria growing before cooking then it would be killed but there could be some residual material (dead bacteria) that could still make a person ill. I'm not familiar with the strain listed in the article but if it's one that just make you have the runs then it could easily be from the above.
Also there's lots of possibilities as to why the chicken was not hot.
1. Was cooked to 165 as whole bird then pulled/shredded and put in pans with sauce. But then the temp was probably 120 or so. Hopefully it was put back in the cooker until it again hit 165. I see this with pork all the time. 180 butts are 125 after pulling and saucing.
2. Meat was pulled from smoker in pans to deliver and sat in a vehicle for an hour before getting to the site. Now if in a Cambro no problem but if not it could be a problem.
And the list goes on and on as to why temps were off. But clearly the client had some responsibility leaving it out unheated for 5 hours.
Retired competition cook. BBQ mentor.