<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 5.8.4

Error message:
Ошибка доступа к памяти.

Трассировка стека:
(0061B580) C2447_0
(00861DD6) C5073_3
(00863E3E) ____ExceptionHandler
(00860BF8) __ExceptionHandler
(0008112F) ntdll.dll
(0006ECCA) ntdll.dll.KiUserExceptionDispatcher
(00622404) _ssh_agent_forwarding_permitted
(00627D07) _sshfwd_x11_is_local
(0062808F) _sshfwd_x11_is_local
(0061B4A2) C2447_0
(0061B655) C2447_0
(0061B970) _ssh_connshare_log
(0064A341) _select_result
(006FAD23) TSecureShell::HandleNetworkEvents
(006FAFE6) TSecureShell::ProcessNetworkEvents
(006FA5D7) TSecureShell::WaitForData
(006F59E1) TSecureShell::Init
(006F52B6) TSecureShell::Open
(007332FF) TSFTPFileSystem::Open
(0076DC27) TTerminal::Reopen
(006C5681) TTerminalThread::TerminalReopenEvent
(006C0648) TSignalThread::Execute
(00098247) Userinterface::C20_0
(000152C2) KERNEL32.DLL.BaseThreadInitThunk
(0005E09A) ntdll.dll
(0005E062) ntdll.dll

(00862441) C5073_3
(00863A1B) _ReThrowException
(006F5AEF) TSecureShell::Init
(006F52B6) TSecureShell::Open
(007332FF) TSFTPFileSystem::Open
(0076DC27) TTerminal::Reopen
(006C5681) TTerminalThread::TerminalReopenEvent
(006C0648) TSignalThread::Execute
(00098247) Userinterface::C20_0
(000152C2) KERNEL32.DLL.BaseThreadInitThunk
(0005E09A) ntdll.dll
(0005E062) ntdll.dll
Аутентификац%D

The problem happens rarely. I cannot reproduce it.