After Disposing older Runspace and creating a new runspace, new runspace is having a connections of old runspace

When we create a runspace(runspace1) and Powershell(powershell1) session and then Connect to exchnage online using Connect-ExchangeOnline cmdlet. And then dispose the runspace and create a new runspcae(runspace2) and new Powershell session(powershell2) and run Get-ConnectionInformation cmdlet, it shows the connection details of exchange online which was created by runspace1.
And if we execute any cmdlet(Ex: Get-User,Set-Mailbox) with the runspace2 it is giving the error - The term 'Get-User' is not recognized as the name of a cmdlet, function, script file, or operable program.
Below is the detailed snippet.

Is this the expected scenario?

//create runspace1
                InitialSessionState iss = InitialSessionState.CreateDefault();
                iss.ExecutionPolicy = Microsoft.PowerShell.ExecutionPolicy.RemoteSigned;
                Runspace runspace1 = RunspaceFactory.CreateRunspace(iss);
                runspace1.Open();


                //create powershell session
                PowerShell powershell1 = PowerShell.Create();
                powershell1.Runspace = runspace1;


                //Creating secure password 
                StringBuilder cmd = new StringBuilder("$sec=ConvertTo-SecureString ");
                cmd.Append("'");
                cmd.Append("*******");
                cmd.Append("'");
                cmd.Append(" -AsPlainText -Force");
                powershell1.AddScript(cmd.ToString());
                Collection<PSObject> connectionResult1 = powershell1.Invoke();
                powershell1.Commands.Clear();
                cmd.Clear();

                //create credential.
                cmd.Append("$mycreds = New-Object System.Management.Automation.PSCredential(\"" + "****@*****.onmicrosoft.com" + "\",$sec)");
                powershell1.AddScript(cmd.ToString());
                Collection<PSObject> connectionResult2 = powershell1.Invoke();
                powershell1.Commands.Clear();
                cmd.Clear();

                //Connect to exchange online
                cmd.Append("Connect-ExchangeOnline -Credential $mycreds");
                powershell1.AddScript(cmd.ToString());
                Collection<PSObject> connectionResult3 = powershell1.Invoke();
                powershell1.Commands.Clear();
                powershell1.Streams.ClearStreams();
                cmd.Clear();



                // Get connection info from first powershell session
                powershell1.AddScript("Get-ConnectionInformation");
                Collection<PSObject> connectionResult4 = powershell1.Invoke();
                powershell1.Commands.Clear();
                powershell1.Streams.ClearStreams();
                powershell1.Dispose();
                powershell1 = null;

                //Discposing runspace1 
                runspace1.Close();
                 runspace1.Dispose();
                 runspace1 = null;
               

                //Creating 2nd runspace2 and powershell session 2
                InitialSessionState iss2 = InitialSessionState.CreateDefault();
                iss2.ExecutionPolicy = Microsoft.PowerShell.ExecutionPolicy.RemoteSigned;
                Runspace runspace2 = RunspaceFactory.CreateRunspace(iss2);
                runspace2.Open();
                PowerShell powershell2 = PowerShell.Create();
                powershell2.Runspace = runspace2;



                powershell2.AddScript("Get-ConnectionInformation");
                Collection<PSObject> connectionResult5 = powershell2.Invoke();
                powershell2.Commands.Clear();
                powershell2.Streams.ClearStreams();
                List<string> sessionIds = new List<string>();

                if (connectionResult5.Count > 0)
                {
                    foreach (PSObject sessionItem in connectionResult5)
                    {
                        string session = JsonConvert.SerializeObject(sessionItem.ImmediateBaseObject);
                        JObject sessionJsonObject = JObject.Parse(session);
                        string id = (string)sessionJsonObject["ConnectionId"];
                        sessionIds.Add(id);
                    }
                }

//executing cmdlet with runspace2
                String cmd1 = "Get-User";
                powershell2.AddScript(cmd1);
                Collection<PSObject> connectionResult6 = powershell2.Invoke();
                PSInvocationStateInfo info1 = powershell2.InvocationStateInfo;
                if (info1.State == PSInvocationState.Completed)
                {
                    if (powershell2.HadErrors && powershell2.Streams.Error.Count > 0)
                    {
                        foreach (var value in powershell2.Streams.Error)
                        {
                            if (value != null)
                            {
                                StringBuilder errors = new StringBuilder();
                                errors.AppendLine(value.InvocationInfo != null
                                    ? value.InvocationInfo.MyCommand.Name : cmd1.ToString());
                                if (value.Exception.Message != null)
                                {
                                    errors.AppendLine(" : " + value.Exception.Message);
                                }
                            }
                        }

                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e);
            }