Invalid access to memory - TTerminalManager::CloseAutheticateForm

<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 5.19.3

Error message:
Invalid access to memory.

Stack trace:
(000B02E1) TTerminalManager::CloseAutheticateForm
(00FC379A) C5294_3
(00FC5802) ____ExceptionHandler
(00FC25BC) __ExceptionHandler
(0003EE3E) ntdll.dll.ZwWow64CallFunction64
(0003F5BA) ntdll.dll.KiUserExceptionDispatcher
(000AF9E9) TTerminalManager::~TTerminalManager
(000AF39C) TTerminalManager::DestroyInstance
(00109014) Execute
(00002658) wWinMain
(00FC17AD) C5162_0
(00059B8D) ntdll.dll
(00059B55) ntdll.dll

The problem happens rarely. I cannot reproduce it.

<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 5.21.5

Error message:
Ogiltig åtkomst till minnet.

Stackspår:
(000B3299) TTerminalManager::CloseAutheticateForm
(00FDC86E) C5412_0
(00FDE8D6) ____ExceptionHandler
(00FDB690) __ExceptionHandler
(00087B7F) ntdll.dll
(00074001) ntdll.dll.KiUserExceptionDispatcher
(000B288D) TTerminalManager::~TTerminalManager
(000B222C) TTerminalManager::DestroyInstance
(0010B181) Execute
(000027FA) wWinMain
(00FDA881) __wstartup
(00066BBC) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066B89) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.

<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 5.21.7

Error message:
Invalid access to memory.

Stack trace:
(000B32CD) TTerminalManager::CloseAutheticateForm
(00FDF7C2) C5412_0
(00FE182A) ____ExceptionHandler
(00FDE5E4) __ExceptionHandler
(00087A7F) ntdll.dll
(000740D1) ntdll.dll.KiUserExceptionDispatcher
(000B28C1) TTerminalManager::~TTerminalManager
(000B2260) TTerminalManager::DestroyInstance
(0010B1B5) Execute
(000027FA) wWinMain
(00FDD7D5) __wstartup
(00066C6C) ntdll.dll.RtlGetAppContainerNamedObjectPath
(00066C39) ntdll.dll.RtlGetAppContainerNamedObjectPath

The problem happens rarely. I cannot reproduce it.