<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 5.20.4

Error message:
Invalid access to memory.

Stack trace:
(00378108) System::Internal::Strhlpr::UnicodeAssign
(0008784F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(0001FBB9) TCustomScpExplorerForm::UpdateSessionData
(00050E9F) TScpCommanderForm::UpdateSessionData
(0001FB72) TCustomScpExplorerForm::UpdateTerminal
(00050E17) TScpCommanderForm::UpdateTerminal
(0001F567) TCustomScpExplorerForm::DoCollectWorkspace
(0002B46C) TCustomScpExplorerForm::FormClose
(0023A79B) Vcl::Forms::TCustomForm::DoClose
(00280DAD) Vcl::Controls::TWinControl::WndProc
(0023B274) Vcl::Forms::TCustomForm::WndProc

The problem happens rarely. I cannot reproduce it.