An Azure service that is used to manage and protect cryptographic keys and other secrets used by cloud apps and services.
Your PowerShell output confirms that Key Vault stored 12 months / 24% immediately after the save; it does not yet prove that the policy later reverted.
When the portal next shows 6 months / 50%, immediately run:
Get-AzKeyVaultCertificatePolicy -VaultName <vault> -Name <certificate> |
Select-Object ValidityInMonths, RenewAtPercentageLifetime, Updated
If this still returns 12 / 24, the portal view is stale—the policy itself did not change. If it returns 6 / 50, search the Key Vault audit logs around that timestamp for the certificate-policy update and inspect the identity, client information, caller IP, and correlation ID. Allow up to about ten minutes for audit records to arrive. Also check deployment pipelines, IaC, policy remediation, and the integrated CA template, which may enforce its own issuance settings.
One important detail: RenewAtPercentageLifetime = 24 means renew after 24% of the lifetime has elapsed, not when 24% remains. If no update is audited but the API value truly changes, open a support case with both policy captures and exact timestamps.