Diagnosis
This is a known design trait. The warming plate on this model runs at a fixed, high temperature and lacks an adjustable thermostat.
How to Fix It
Do not leave the carafe on the plate for more than 30-40 minutes after brewing. Pour all coffee into a thermal carafe or insulated server immediately after the brew cycle finishes.
If That Didn't Work
If the plate is so hot it's a safety hazard or turns off randomly, the thermal cut-off switch might be faulty. This requires a base replacement—contact Ninja support.
Heads Up
The glass carafe is not designed for prolonged high heat. Leaving it empty on the hot plate can cause it to crack or shatter.