Start button & 8hr button on my 6qt crock pot come on for 6 seconds then shut off for 30secs? It is getting hot? What's the issue?

This issue with your crock pot could be due to a malfunctioning thermal fuse or a problem with the heating element. The thermal fuse is a safety device that shuts off the power to the heating element if it becomes too hot. If the thermal fuse is faulty, it can cause the crock pot to shut off and turn on repeatedly.
It is also possible that there is an issue with the heating element itself. If the element is damaged or not functioning correctly, it may cause the crock pot to turn off and on intermittently.
To diagnose and fix the problem, it is recommended to take the crock pot to a professional appliance repair technician. They can test the thermal fuse and heating element to determine the cause of the issue and make the necessary repairs.