<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 5.19.6

Error message:
Invalid access to memory.

Stack trace:
(00D3CA78) TSecureShell::SshFallbackCmd
(00FC4C46) C5294_3
(00FC6CAE) ____ExceptionHandler
(00FC3A68) __ExceptionHandler
(00087B7F) ntdll.dll
(00074001) ntdll.dll.KiUserExceptionDispatcher
(00CF76E7) TTerminalThread::TerminalOpenEvent
(00CF2554) TSignalThread::Execute
(000C183B) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066BBC) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066B89) ntdll.dll.RtlGetAppContainerNamedObjectPath

(00FC52B1) C5294_3
(00FC688B) _ReThrowException
(00DC312D) TTerminal::Open
(00CF76E7) TTerminalThread::TerminalOpenEvent
(00CF2554) TSignalThread::Execute
(000C183B) Userinterface::C20_0
(0001EA27) KERNEL32.DLL.BaseThreadInitThunk
(00066BBC) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066B89) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.