sensors/vehicle_air_data: only trigger the sensor fallback when the baro_fault flag switches from 0 -> 1

src/modules/sensors/vehicle_air_data/VehicleAirData.cpp

@@ -200,7 +200,7 @@ void VehicleAirData::Run()
 					}
 
 					if (estimator_status_flags_updated && _selected_sensor_sub_index >= 0 && _selected_sensor_sub_index == uorb_index
-					    && estimator_status_flags.cs_baro_fault) {
+					    && estimator_status_flags.cs_baro_fault && !_last_status_baro_fault) {
 						_priority[uorb_index] = 1; // 1 is min priority while still being enabled
 					}
 
@@ -225,6 +225,10 @@ void VehicleAirData::Run()
 		}
 	}
 
+	if (estimator_status_flags_updated) {
+		_last_status_baro_fault = estimator_status_flags.cs_baro_fault;
+	}
+
 	// check for the current best sensor
 	int best_index = 0;
 	_voter.get_best(time_now_us, &best_index);

src/modules/sensors/vehicle_air_data/VehicleAirData.hpp

@@ -126,6 +126,8 @@ private:
 
 	float _air_temperature_celsius{20.f}; // initialize with typical 20degC ambient temperature
 
+	bool _last_status_baro_fault{false};
+
 	DEFINE_PARAMETERS(
 		(ParamFloat<px4::params::SENS_BARO_QNH>) _param_sens_baro_qnh,
 		(ParamFloat<px4::params::SENS_BARO_RATE>) _param_sens_baro_rate