Get-PnPHubSite doesn't return NULL then the specified URL or Id points to a site that is not a hub site

Actual behavior

Get-PnPHubSite currently returns a not-null respons when calling using a valid URL to a site that is not a hub site. I would expect a null value

Steps to reproduce behavior

part of an Azure Function:
$SPOAdminUrl = "the URL of the SP admin site"
$siteUrl = "contoso.sharepoint.com/sites/nothubsite"
$adminConn = Connect-PnPOnline -Url $SPOAdminUrl -Interactive -ClientId $PnPClientId -ReturnConnection
$hubSite = Get-PnPHubSite -Identity $siteUrl -Connection $adminConn -ErrorAction Stop
if($hubSite) #this fails as $hubSite is not null
{
$body += "The site $siteUrl is already registered as a hub site"
$StatusCode = [HttpStatusCode]::AlreadyReported
}

What is the version of the Cmdlet module you are running?

3.1.0

Which operating system/environment are you running PnP PowerShell on?

• Windows
• Linux
• MacOS
• Azure Cloud Shell
• Azure Functions
• Other : please specify

Start at the Get-PnPHubSite cmdlet entry point and reproduce the reported call with a valid URL or Id for a site that is not a hub site. Verify the behavior for both non-hub and hub sites, and consider the issue complete when the former returns null while the latter still returns its hub-site result.