<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 5.7.6

Error message:
Invalid access to memory.

Stack trace:
(001CF042) Vcl::Forms::TScreen::
(0005A5DA) ntdll.dll
(0000F12E) ntdll.dll.KiUserExceptionDispatcher
(00711B6E) TTerminal::CommandError
(00711901) TTerminal::CommandError
(0071AA72) TTerminal::ChangeDirectory
(007108AA) TTerminal::SetCurrentDirectoryW
(00614DFA) TUnixDirView::SetPath
(0002167E) TCustomScpExplorerForm::RemotePathComboBoxItemClick
(0043B011) Tbxextitems::TTBXComboBoxItem::DoListClick
(003402A8) System::Classes::_18201
(000152F7) USER32.dll
(00015D35) USER32.dll
(000167BF) USER32.dll
(00016885) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.