I've been working with the camera for a few hours working on settings and I notice that the camera cooler stays about -8 at best. My usual setting for the STX and STl have been -20. What is suggested for max on the AC4040BSI?
The camera has a Delta T of approximately 35C at sea level. So -15C is typical for ambient temperature of +20C. What's your ambient temperature (and altitude)? Have you checked the fan is actually running? (Am not sure if you are on site or remote). Typically, set the cooler to -15C, assuming ambient <20C. The glow does not reduce much at temperatures below that.
It would likely overheat without the fan. The lower air pressure at altitude will have some impact on cooling delta.