Potential fix for issue 4241

CHANGELOG.md

@@ -46,6 +46,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 - `Clear-PnPRecycleBinItem` , `Move-PnPRecycleBinItem` and `Restore-PnPRecycleBinItem` cmdlets now use PnP Core SDK for processing requests. [#4393](https://github.com/pnp/powershell/pull/4393/)
 - `Get-PnPSearchCrawlLog` cmdlet now shows a warning in case application permissions are used. [#4391](https://github.com/pnp/powershell/pull/4391)
 - All Power Platform cmdlets no longer require an environment to be specified. If omitted, the default environment will be retrieved and used. [#4415](https://github.com/pnp/powershell/pull/4415)
+- When passing in an existing connection using `-Connection` on `Connect-PnPOnline`, the clientid from the passed in connection will be used for the new connection [#4425](https://github.com/pnp/powershell/pull/4425)
 
 ### Fixed
 

documentation/Connect-PnPOnline.md

@@ -405,6 +405,8 @@ Accept wildcard characters: False
 ### -Connection
 Optional connection to be reused by the new connection. Retrieve the value for this parameter by either specifying -ReturnConnection on Connect-PnPOnline or by executing Get-PnPConnection.
 
+When passed in, the ClientId/AppId used for the passed in connection will be used for the new connection. It will override any -ClientId or -AppId parameter passed in.
+
 ```yaml
 Type: PnPConnection
 Parameter Sets: Credentials, SharePoint ACS (Legacy) App Only, App-Only with Azure Active Directory, App-Only with Azure Active Directory using a certificate from the Windows Certificate Management Store by thumbprint, SPO Management Shell Credentials, DeviceLogin, Interactive login for Multi Factor Authentication, Environment Variable

src/Commands/Base/ConnectOnline.cs

@@ -356,6 +356,13 @@ protected void Connect(ref CancellationToken cancellationToken)
                 }
             }
 
+            if (ParameterSpecified(nameof(Connection)))
+            {
+                // Reuse some parameters of the passed in connection
+                WriteVerbose("Reusing some of the connection parameters from passed in connection");
+                ClientId = Connection.ClientId;
+            }
+
             if (AzureEnvironment == AzureEnvironment.Custom)
             {
                 SetCustomEndpoints();