Throttle_nudge for plane

Hello guys!
I am using herelink remote (central throttle stick) with plane using an airspeed sensor. I set Trim_arspd_cm at 13 m/s and Throttle_nudge is enable (1). Ardupilot describe that below: “When enabled, this uses the throttle input in auto-throttle modes to ‘nudge’ the throttle or airspeed to higher or lower values. When you have an airspeed sensor the nudge affects the target airspeed, so that throttle inputs above 50% will increase the target airspeed from TRIM_ARSPD_CM up to a maximum of ARSPD_FBW_MAX. When no airspeed sensor is enabled the throttle nudge will push up the target throttle for throttle inputs above 50%”
But whenever I enter cruise mode with herelink stick in neutrel, the plane seems not fly right with target speed (it fly faster!) So what was wrong? Pls help me. Thanks!
P/S: I set Arspd_FBW_Min at 12 m/s and Arspd_FBW_Max at 25 m/s, Trim_arspd_cm at 13 m/s.