<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.15.9

Error message:
メモリのアクセス違反

スタック トレース:
(0027827F) Vcl::Controls::TWinControl::PrecedingWindow
(0092812A) C5157_3
(0092A192) ____ExceptionHandler
(00926F4C) __ExceptionHandler
(00087D6F) ntdll.dll
(00073211) ntdll.dll.KiUserExceptionDispatcher
(007511B3) TInformationUserAction::Execute
(0074FA9D) TTerminalThread::TerminalOpen
(000AB412) TTerminalManager::ConnectActiveTerminalImpl
(000AB538) TTerminalManager::ConnectActiveTerminal
(000ABDB4) TTerminalManager::DoSetActiveTerminal
(000ABB3E) TTerminalManager::SetActiveTerminal
(00018CA9) TCustomScpExplorerForm::NewSession
(0002025C) TCustomScpExplorerForm::SessionTabSwitched
(000202B0) TCustomScpExplorerForm::SessionsPageControlChange
(00279219) Vcl::Controls::TWinControl::WndProc
(00274310) Vcl::Controls::TControl::Perform
(0027937F) Vcl::Controls::_17076
(00279219) Vcl::Controls::TWinControl::WndProc
(002336E0) Vcl::Forms::TCustomForm::WndProc

(0027BEFC) Vcl::Controls::TWinControl::CMInvalidate
(00087D6F) ntdll.dll
(00073211) ntdll.dll.KiUserExceptionDispatcher
(00279219) Vcl::Controls::TWinControl::WndProc
(00274310) Vcl::Controls::TControl::Perform
(0027BE25) Vcl::Controls::TWinControl::Invalidate
(00279219) Vcl::Controls::TWinControl::WndProc
(002336E0) Vcl::Forms::TCustomForm::WndProc

The problem happens rarely. I cannot reproduce it.