What is the built-in compressor protection feature and why is my thermostat displaying 'Cool On' flashing?

The built-in compressor protection feature forces the compressor to wait a few minutes before restarting after a shutdown to prevent equipment damage. During this brief wait period, the thermostat will flash 'Cool On' (or 'Heat On' for heat pump systems) until the wait period ends and the compressor can safely turn back on. This flashing message is also used for startup delay protection after AC power loss.