Get-AzWebAppSnapshot throws "String was not recognized as a valid DateTime" error

[Ivan Buzyka]

I am implementing Release Pipeline and wanted to use App Service Snapshots feature (which is currently in preview). According to the documentation it should be easy, but I faced an issue at very first step when just tried to get snapshot using appropriate Az commandlet.

Note: app, that I would like to get snapshots from is in P tier and have snapshots (at least they can be seen on Backup blade)

Here what I am trying to run:

Get-AzWebAppSnapshot -ResourceGroupName ibu-testsnapshot -Name ibu-testsnapshot -Slot production

An the exception in Powershell:

Get-AzWebAppSnapshot : String was not recognized as a valid DateTime.
At line:1 char:1
+ Get-AzWebAppSnapshot -ResourceGroupName weu-prd-xc2 -Name weu-prd-xc2 ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : CloseError: (:) [Get-AzWebAppSnapshot], FormatException
    + FullyQualifiedErrorId : Microsoft.Azure.Commands.WebApps.Cmdlets.BackupRestore.GetAzureWebAppSnapshot

I suppose it is expecting some parameter to be DateTime, but which one? Event in context help there is nothing about that:

Does anybody have any idea what can be the case?