S6813-48X6C：设备风扇告警

在设备上看到有告警The airflow direction of The two Power Fan is Different on slot 2 ,please check it.

但是display fan里看都是正常的，请问要如何解决这个告警

<NB_IDC_YF_A04_ACC01>dis fan 

Slot 2: 

 Fan 1: 

 State : Normal

 Airflow Direction: Port-to-power

 Prefer Airflow Direction: Port-to-power

 Fan 2: 

 State : Normal

 Airflow Direction: Port-to-power

 Prefer Airflow Direction: Port-to-power

 Fan 3:  

State : Normal

 Airflow Direction: Port-to-power

 Prefer Airflow Direction: Port-to-power

<NB_IDC_YF_A04_ACC01>dis power

 Slot 2:

 PowerID State Mode Current(A) Voltage(V) Power(W)

  1 Normal -- -- -- --

 2 Normal AC -- -- --