Invalid access to memory - _conf_get_int

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WinSCP 6.1.2

Error message:
Invalid access to memory.

Stack trace:
(00C7D500) _conf_get_int
(01003DEA) C6083_0
(01005E52) ____ExceptionHandler
(01002C0C) __ExceptionHandler
(0008792F) ntdll.dll
(00073F81) ntdll.dll.KiUserExceptionDispatcher
(00C6F9AC) _ssh2transport_finalise_exhash
(00C70373) _ssh2_transport_notify_auth_done
(00C6C4A8) _winscp_query
(00D6C2B0) TSecureShell::Idle
(00DF5AEF) TTerminal::Idle
(000C1CA9) TTerminalManager::Idle
(0001B8D6) TCustomScpExplorerForm::Idle
(00053267) TNonVisualDataModule::DoIdle
(00053224) TNonVisualDataModule::SessionIdleTimerTimer
(0021564C) System::Classes::_18201
(00040039) USER32.dll
(00036FE5) USER32.dll
(00034D45) USER32.dll
(00034B0B) USER32.dll.DispatchMessageW

(01004455) C6083_0
(01005A2F) _ReThrowException
(000C1CF2) TTerminalManager::Idle
(0001B8D6) TCustomScpExplorerForm::Idle
(00053267) TNonVisualDataModule::DoIdle
(00053224) TNonVisualDataModule::SessionIdleTimerTimer
(0021564C) System::Classes::_18201
(00040039) USER32.dll
(00036FE5) USER32.dll
(00034D45) USER32.dll
(00034B0B) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.