1.Confirm the old and current software version of the storage, there is such problem only when upgrade from the version which doesn't have the enclosure ID refresh function to a version which has enclosure ID refresh function.
Below versions have the enclosure ID refresh function:
OceanStor V3 Series V300R001C20SPC100 and later versions
OceanStor V3 Series V300R002C10SPC200 and later versions
OceanStor V3 Series V300R003C00SPC100 and later versions
2.Confirm if expanded the new disk enclosure before.
3.Confirm the network topology of the disk enclosure:
From the SAS interface of Controller A to each disk enclosures, check if the deepth and the display ID are consistent and also if it is consistent with controller B.