ISCSI based datastores/LUNs will be removed from ESXi hosts after a Permanent Device Loss (PDL) scenario. This is specific to iSCSI based storage targets which support "Permanent Device Loss Event" reporting.
ESXi 9.1
vCenter Server 9.1
Perform a Storage Adapter rescan from vCenter or ESXi after recovering from PDL. See Performing a rescan of the storage on an ESXi host for details.