メモリのアクセス違反 - Driveview::TDriveView::NodePathName

<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 6.5.5

Error message:
メモリのアクセス違反

スタック トレース:
(00139BC4) System::UStrAsg
(0008822F) ntdll.dll
(00074711) ntdll.dll.KiUserExceptionDispatcher
(00523DEF) Driveview::TDriveView::NodePathName
(0050EBE4) Customdriveview::TCustomDriveView::GetDirectory
(0050E917) Customdriveview::TCustomDriveView::ValidateDirectory
(0044D67F) Vcl::Extctrls::TTimer::Timer
(00204C90) System::Classes::_18364
(00040C09) USER32.dll
(000372C5) USER32.dll
(00035B6B) USER32.dll
(0003569B) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.