BQ25710: IN AC only mode,VSYS output is 2V.

Part Number: BQ25710

IN AC only mode,VBUS = 20V,VSYS output is 2V, the buck no works,and the REGN LDO output is 5.6V, this phenomenon is abnormal.

Now, I plug in the battery,now the VSYS is 14.X V ,and then I plug out the battery, the VSYS is 12.2V, and the REGN LDO output is 6V.

Have you seen this phenomenon?