Check if customer is using Recoverpoint from EMC.
Recoverpoint is a Storage Replication software to replicate LUNs from one site to other site.
As per EMC documentation;
" In the RecoverPoint system, data consistency and write-order fidelity are maintained across all volumes, by replication sets.
Therefore, when you wish to add storage capacity to a particular volume, you must resize all of the volumes on the replication set.
When a LUNs storage capacity changes on the host storage system, the volume representing the LUN in RecoverPoint must be removed from and then re-added to, the RecoverPoint System.
For the change in the LUN size to be reflected in RecoverPoint. "
In this case this applied as well for ESXI/vCenter, we need to remove the LUN from the replication set and perform a Rescan of the storage.
After doing so, we should be able to report back the correct size.