diff --git a/src/modules/flight_mode_manager/tasks/Utility/StickAccelerationXY.cpp b/src/modules/flight_mode_manager/tasks/Utility/StickAccelerationXY.cpp
index c36d024ead..c8b45af35d 100644
--- a/src/modules/flight_mode_manager/tasks/Utility/StickAccelerationXY.cpp
+++ b/src/modules/flight_mode_manager/tasks/Utility/StickAccelerationXY.cpp
@@ -204,6 +204,14 @@ void StickAccelerationXY::lockPosition(const Vector3f &pos, const matrix::Vector
 	const bool moving = _velocity_setpoint.norm_squared() > FLT_EPSILON;
 	const bool position_locked = Vector2f(_position_setpoint).isAllFinite();
 
+	if (!pos.isAllFinite()) {
+		// position is invalid. We may still enter here through a mode
+		// requiring only relaxed local position. In this case, no
+		// position locking can happen, so we give no position setpoint.
+		_position_setpoint.setNaN();
+		return;
+	}
+
 	// lock position
 	if (!moving && !position_locked) {
 		_position_setpoint = pos.xy();