Invalid access to memory

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WinSCP 6.1.1

Error message:
Invalid access to memory.

Stack trace:
(0029466B) System::DoneExcept
(0009783F) ntdll.dll
(000777B1) ntdll.dll.KiUserExceptionDispatcher
(00214D98) System::Classes::_18201
(000313B1) USER32.dll
(000221B1) USER32.dll
(00020A70) USER32.dll
(000205BB) USER32.dll.DispatchMessageW

(00294258) System::HandleAnyException
(0009783F) ntdll.dll
(000777B1) ntdll.dll.KiUserExceptionDispatcher
(00214D98) System::Classes::_18201
(000313B1) USER32.dll
(000221B1) USER32.dll
(00020A70) USER32.dll
(000205BB) USER32.dll.DispatchMessageW

Status: all_insignificant

The problem happens rarely. I cannot reproduce it.