Grey - Trigger Inactive:

This means that the trigger is not in a position to watch yet

E.g. you want to watch for then internet being disconnected, but it's already disconnected.

If the internet became connected this trigger would automatically change to green and start watching.

Amber - Trigger Paused (but ready):

This means that the trigger has been paused and will not trigger.

E.g. you are monitoring for the internet to be disconnected, it was watching, but you paused the trigger.

Green - Trigger Watching:

This means the trigger is actively watching whatever you want it to watch

E.g. you are connected to the Internet and are watching for it to be disconnected

Red - Trigger Triggering:

This means the trigger is has been watching (green), and has detected the state change

E.g. you were connected to the internet, but have become disconnected

This status would trigger the chosen shortcut to run