Can't pipe Azcontext object in azure function environment to output/log

I have below azure ps function. Looks like the object returned to caller, but the returned object can't pipe to log. Is this intended?
if run the script not in ps function environment, the caller can receive the object can pipe the return to output
```
using namespace System.Net
using namespace Microsoft.Azure.Functions.PowerShellWorker
param($Request, $TriggerMetadata)
Write-Host "PowerShell http trigger function processed work item"
function Install-Certificate
{
param(
[System.Security.Cryptography.X509Certificates.X509Certificate2]$Certificate,
[string]$StorePath
)
Write-Host "Install-Certificate"
$store = Get-Item $storePath -ErrorAction Stop
try
{
$store.Open([System.Security.Cryptography.X509Certificates.OpenFlags]::ReadWrite)
}
catch
{
throw "Failed to open cert store {0} -- {1}" -f $storePath,$a
}
try
{
$store.add($Certificate)
}
catch
{
throw "Failed to add certificate to cert store {0} -- {1}" -f $storePath,$a
}
$store.close()
Write-Host "End of Install-Certificate"
}

function Connect-CustomerTenant1
{
param(
[Parameter(Mandatory=$true)][string]$SubscriptionId,
[Parameter(Mandatory=$true)][string]$SPNId,
[Parameter(Mandatory=$true)][string]$KeyVaultName,
[string]$TenantId = "72f988bf-86f1-41af-91ab-2d7cd011db47",
[string]$AzureEnvironmentName = "AzureCloud"
)

$cnt = 0
$MaximumRetryCount = 3

$ctx = Connect-AzAccount -Identity -Force
$kvSecret = Get-AzKeyVaultSecret -VaultName $KeyVaultName -Name $SPNId -DefaultProfile $ctx
$kvSecretBytes = [System.Convert]::FromBase64String($kvSecret.SecretValueText)
$certificate = [System.Security.Cryptography.X509Certificates.X509Certificate2]::new($kvSecretBytes, $null, [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::MachineKeySet)

$thumbprint = $certificate.Thumbprint
Write-Host "Thumbprint: $thumbprint"
Install-Certificate -Certificate $certificate -StorePath "Cert:\CurrentUser\My"
do {
$cnt++
$exceptionMessage = $null
try {
Write-Host "Connect-AzAccount..."
$Script:AzContext = Connect-AzAccount -CertificateThumbprint $thumbprint `
-ApplicationId $SPNID -Tenant $TenantID `
-ServicePrincipal -Environment $AzureEnvironmentName `
-SubscriptionId $SubscriptionId -ErrorAction Stop
Write-Host "After Connect-AzAccount ..."
# validate due to bug in az module (bug link: https://github.com/Azure/azure-powershell/issues/9448)
$rglist = Get-AzResourceGroup -DefaultProfile $Script:AzContext
Write-Host "Get $($rglist.Count) resource groups"
Write-Host "After validation ..."
Write-Host "Execution count: $cnt"
Write-Host "context: $($Script:AzContext | Out-String)"
#return
# bug: the axContext does not return to caller
return $Script:AzContext
}
catch
{
Write-Host "AzContext in exception: $(Get-AzContext | Out-String)"
Write-Host "Connect-AzAccount failed, retry count: $cnt"
$exceptionMessage = $_.Exception.Message
Write-Host $exceptionMessage
if($_.Exception.InnerException)
{
Write-Host $_.Exception.InnerException.Message
#$exceptionMessage += $_.Exception.InnerException.Message
}
}
} while ($cnt -lt $MaximumRetryCount)

# Throw an error after $MaximumRetryCount unsuccessful invocations. Doesn't need
# a condition, since the function returns upon successful invocation.
Write-Host "connect-Azacccount failed. retry count: $cnt"
throw "Login validation failed. $exceptionMessage"
}

try
{
$cxt = Connect-CustomerTenant1 -SubscriptionId "e9c08608-0c4f-4a51-8640-968eafc186af" `
-TenantId "72f988bf-86f1-41af-91ab-2d7cd011db47" `
-SPNID "70402f7e-6079-44ef-865f-55315dc7ce19" `
-KeyVaultName "amvmyawang-kv"
if($cxt)
{
$body = $cxt | out-string
#Write-Output "body:"
#Write-Output $body
#Write-Output "Type of cxt: $($cxt.GetType())"
Write-Output "returned cxt in caller:"
Write-output $cxt
Write-Host "context:"
Write-Output $cxt.Context
Write-Host "context | Out-String"
Write-Output $($cxt.Context | fl * | Out-String)
#Write-Output $($cxt.Context | Get-Member)
Write-Host "Hello"

#$rglist = Get-AzResourceGroup -DefaultProfile $cxt
#Write-Output $rglist
}
else {
Write-Host "cxt is null in caller"
}
}
catch
{
Write-Host $_.Exception.Message
}
Push-OutputBinding -Name Response -Value ([HttpResponseContext]@{
StatusCode = [HttpStatusCode]::OK
Body = $body
})

```
output in ps azure function:
2019-08-08T20:30:03.599 [Information] Executing 'Functions.bugrepro' (Reason='This function was programmatically called via the host APIs.', Id=a170dcbe-6062-420f-afc7-907d52a1081c)
2019-08-08T20:30:14.138 [Information] INFORMATION: PowerShell http trigger function processed work item
2019-08-08T20:30:21.155 [Information] INFORMATION: Thumbprint: E03A6AD85BEF21B872C1075EF3B6E5749904F232
2019-08-08T20:30:21.156 [Information] INFORMATION: Install-Certificate
2019-08-08T20:30:21.234 [Information] INFORMATION: End of Install-Certificate
2019-08-08T20:30:21.234 [Information] INFORMATION: Connect-AzAccount...
2019-08-08T20:30:21.993 [Information] INFORMATION: After Connect-AzAccount ...
2019-08-08T20:30:27.473 [Information] INFORMATION: Get 3 resource groups
2019-08-08T20:30:27.476 [Information] INFORMATION: After validation ...
2019-08-08T20:30:27.476 [Information] INFORMATION: Execution count: 1
2019-08-08T20:30:27.477 [Information] INFORMATION: context:
Account SubscriptionName TenantId Environment
------- ---------------- -------- -----------
70402f7e-6079-44ef-865f-55315dc7ce19 TestEA Customer3 72f988bf-86f1-41af-91ab-2d7cd011db47 AzureCloud
2019-08-08T20:30:27.477 [Information] OUTPUT: returned cxt in caller:
2019-08-08T20:30:27.477 [Information] OUTPUT:
2019-08-08T20:30:27.478 [Information] INFORMATION: context:
2019-08-08T20:30:27.478 [Information] INFORMATION: context | Out-String
2019-08-08T20:30:27.478 [Information] INFORMATION: Hello
2019-08-08T20:30:29.490 [Information] Executed 'Functions.bugrepro' (Succeeded, Id=a170dcbe-6062-420f-afc7-907d52a1081c)