diff --git a/libraries/AP_InertialSensor/AP_InertialSensor.cpp b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
index ccc9ac2425..e2855b73d6 100644
--- a/libraries/AP_InertialSensor/AP_InertialSensor.cpp
+++ b/libraries/AP_InertialSensor/AP_InertialSensor.cpp
@@ -1615,6 +1615,7 @@ void AP_InertialSensor::HarmonicNotch::update_params(uint8_t instance, bool conv
     const float center_freq = calculated_notch_freq_hz[0];
     if (!is_equal(last_bandwidth_hz[instance], params.bandwidth_hz()) ||
         !is_equal(last_attenuation_dB[instance], params.attenuation_dB()) ||
+        (params.tracking_mode() == HarmonicNotchDynamicMode::Fixed && !is_equal(last_center_freq_hz[instance], center_freq)) ||
         converging) {
         filter[instance].init(gyro_rate,
                               center_freq,
@@ -1623,7 +1624,7 @@ void AP_InertialSensor::HarmonicNotch::update_params(uint8_t instance, bool conv
         last_center_freq_hz[instance] = center_freq;
         last_bandwidth_hz[instance] = params.bandwidth_hz();
         last_attenuation_dB[instance] = params.attenuation_dB();
-    } else if (!is_equal(last_center_freq_hz[instance], center_freq)) {
+    } else if (params.tracking_mode() != HarmonicNotchDynamicMode::Fixed) {
         if (num_calculated_notch_frequencies > 1) {
             filter[instance].update(num_calculated_notch_frequencies, calculated_notch_freq_hz);
         } else {