Delphi FireDac application blocking with unavailable host - delphi

Question

Source: Delphi XE10; Os: W10; Database server: FB 2_5_1;
I created client application to connect more than one database. My application create TSource->Create TThread -> create DataModule with FDConnection.
Every TSource have own TThread which have own DataModule;
To tests I have two definitions: HostLocal and HostRemote;
My Test:
a)Run: Connection.Open for HostRemote;
b)Next Run: Connection.Open for HostLocal;
When HostRemote is unavailable than HostLocal wait for I dont know for what.
Why unavailable connection blocked another correct connection?
EDIT:
Database Server was updated to 3.0.0
Code:
begin
Application.Initialize;
Application.CreateForm(TFormMain, FormMain);
Application.Run;
end.
unit UnitFormMain;
procedure TFormMain.FormCreate(Sender: TObject);
begin
Source0 := TFormSource.Create(Self);
Source1 := TFormSource.Create(Self);
end;
procedure TFormMain.FormClose(Sender: TObject; var Action: TCloseAction);
begin
FreeAndNil( Source0 );
FreeAndNil( Source1 );
end;
procedure TFormMain.Button1Click(Sender: TObject);
begin
Source0.Show;
Source1.Show;
Source0.ThStart( 0 );
Source1.ThStart( 1 );
end;
unit UnitFormSource;
TFormSource = class(TForm)
Memo: TMemo;
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
th: TMyThread;
public
procedure ThStart( value: Integer );
procedure MyTerminate( Sender: TObject );
end;
...
procedure TFormSource.FormCreate(Sender: TObject);
begin
th := TMyThread.Create( TRUE );
th.OnTerminate := MyTerminate;
th.Priority := TThreadPriority.tpLower;
th.FreeOnTerminate := TRUE;
end;
procedure TFormSource.FormClose(Sender: TObject; var Action: TCloseAction);
begin
FreeAndNil( th );
Action := TCloseAction.caFree;
end;
procedure TFormSource.ThStart(value: Integer);
begin
th.SetSwitch( value );
th.Resume;
Memo.Lines.Add( TimeToStr(Now) + ' Start' );
end;
procedure TFormSource.MyTerminate(Sender: TObject);
begin
Memo.Lines.Add( TimeToStr(Now) + ' Terminate' );
end;
unit UnitThread;
TMyThread = class(TThread)
private
Switch: Integer;
dm: TDMFireBird;
protected
procedure Execute; override;
public
constructor Create(CreateSuspended: Boolean);
destructor Destroy; override;
procedure SetSwitch(value: Integer);
end;
...
constructor TMyThread.Create(CreateSuspended: Boolean);
begin
inherited Create(CreateSuspended);
dm := TDMFireBird.Create(nil);
Switch := -1;
end;
destructor TMyThread.Destroy;
begin
FreeAndNil(dm);
inherited;
end;
procedure TMyThread.Execute;
begin
with dm.FDConnection.Params do
begin
Clear;
Add('DriverID=FB');
end;
case Switch of
0:
with dm.FDConnection.Params do
Add('Protocol=Local');
1:
with dm.FDConnection.Params do
begin
Add('Protocol=TCPIP');
Add('Server=10.0.0.1'); // unavailable connection - server not exist
Add('Port=3050');
end;
end;
with dm.FDConnection.Params do
begin
Add('Database=D:\temp\test.fdb');
Add('User_Name=SYSDBA');
Add('Password=masterkey');
end;
try
dm.FDConnection.Open;
except
// to-do: update error message
end;
end;
procedure TMyThread.SetSwitch(value: Integer);
begin
Switch := value;
end;
unit UnitDMFireBird;
TDMFireBird = class(TDataModule)
FDConnection: TFDConnection;
FDTransaction: TFDTransaction;
private
{ Private declarations }
public
{ Public declarations }
end;
Test no.1
Code:
Source0.ThStart( 0 );
// Source1.ThStart( 1 );
Result for Source0:
14:46:20 Start
14:46:20 Terminate
Result for Source1: no result
Comment: At the same time first connection was opened;
Test no.2
Code:
Source0.ThStart( 0 );
Source1.ThStart( 1 );
Result for Source0:
14:48:16 Start
14:48:40 Terminate
Result for Source1:
14:48:16 Start
14:48:40 Terminate
Comment: Terminate for both at the same time.
My question. Why one blocked another ? Why (for test no.2) first correct connection wait for second unavailable connection? In test no.2 first connection should to open like in test no.1 -> fast, without wait.