Remove-AzDenyAssignment: throws "Cannot find an overload for List`1" after confirming delete (DA does delete)

[jruttle]

Description

Remove-AzDenyAssignment throws a runtime error after the user confirms the delete prompt:

Cannot find an overload for "List`1" and the argument count: "<N>".

The argument count varies by call site (observed: 7, 8, 9). The deny assignment is removed server-side (verified via REST GET → 404), so the error appears to be in the cmdlet's response-handling code, not in the underlying API call.

Repro

Tested against the Debug build from PR #29340 (Az.Resources 9.0.3) in PowerShell 7 on Windows.

Import-Module C:\src\azure-powershell\artifacts\Debug\Az.Resources\Az.Resources.psd1 -Force
Connect-AzAccount -Tenant <tenant> -Subscription <sub>

# Case 1 - argument count "7"
$da = New-AzDenyAssignment -Scope "/subscriptions/<sub>" -DenyAssignmentName "case1" -Description "x" `
        -Action @("Microsoft.Storage/storageAccounts/delete") `
        -Principal @{ Id = "<oid>"; Type = "User" }
Remove-AzDenyAssignment -Id $da.Id   # answer Y at prompt
# -> Cannot find an overload for "List`1" and the argument count: "7".

# Case 2 - argument count "8"  (using -DenyAssignmentName + -Scope)
Remove-AzDenyAssignment -DenyAssignmentName $da.DenyAssignmentName -Scope $da.Scope
# -> Cannot find an overload for "List`1" and the argument count: "8".

# Case 3 - argument count "9"  (pipeline delete)
Get-AzDenyAssignment -Scope "/subscriptions/<sub>/resourceGroups/<rg>" | Remove-AzDenyAssignment
# -> Cannot find an overload for "List`1" and the argument count: "9".

In every case, a follow-up Get-AzDenyAssignment -Id $da.Id returns 404 — the DA is deleted, but the cmdlet returns a terminating error to the user.

Expected

Cmdlet returns silently (or returns a removed-resource object) on successful delete.

Actual

Cmdlet throws Cannot find an overload for "List\1"` after the server has already accepted the DELETE.

Impact

• Customers using Remove-AzDenyAssignment see an apparent failure even though the operation succeeded
• Pipeline scenarios (Get | Remove) are broken — first failure terminates pipeline
• Blocks PowerShell GA

Related

• PR Add New-AzDenyAssignment and Remove-AzDenyAssignment cmdlets #29340 introduced *-AzDenyAssignment cmdlets
• See companion bugs: -Confirm:$false ignored; non-idempotent delete-of-missing

[jruttle]

Closing — filed in error. Will be addressed via a follow-up PR by the original author of PR #29340.