Possible Warnings for gps for yaw

Recently I managed to attain gps for yaw, and I wanted to know what are possible warnings,errors, pre flight checks that can happen in case the gps for yaw does not work, like if the gps stops, maybe the drone hits a tree and the gps antenna is dropped,what kind of message I am supposed to see in mission planner, or if it would be necessary to add a plugin to show these messages.