Volume Snapshot Fails After First Successful Snapshot – (XCP-ng 8.3, CloudStack 4.21)

### problem

We are encountering an issue while creating volume snapshots on VMs hosted on XCP-ng 8.3 with FC primary storage.
The first snapshot is created successfully, however any subsequent snapshot attempt fails.

Error
The snapshot job fails with the following error:
failed to getVhdParent with args isISCSI

### versions

Component Version
CloudStack 4.21
Hypervisor XCP-ng 8.3
Storage Type Pre-setup Storage over FC
Primary Storage Fibre Channel (FC)

### The steps to reproduce the bug

snapshot of the volume → Success.
Attempt to create the second snapshot of the same volume → Failure.

Logs:
[logs.txt](https://github.com/user-attachments/files/25788703/logs.txt)

### What to do about it?

_No response_

Inizia leggendo il file logs.txt allegato e riproduci la sequenza: crea uno snapshot del volume, quindi prova a crearne un secondo sullo stesso volume nella configurazione XCP-ng e FC indicata. Traccia l’errore segnalato “getVhdParent with args isISCSI” nel percorso dello snapshot. L’attività è completata quando snapshot consecutivi vengono creati correttamente senza questo errore.

Scritto dal modello di indicizzazione a partire dal testo della issue.