Invalid access to memory - _RtlSecureZeroMemory

Pulling off large file 1Gb or larger from FTP site.
WinSCP 5.19.6

Error message:
Invalid access to memory.

Stack trace:
(00C5FA5B) _RtlSecureZeroMemory
(00FC4C46) C5294_3
(00FC6CAE) ____ExceptionHandler
(00FC3A68) __ExceptionHandler
(0008788F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(00C5FA1F) C2743_0
(00C5C829) _strbuf_free
(00C0482B) _free_prompts
(00C21F7A) _ssh2_userauth_set_transport_layer
(00C31331) _ssh_ppl_free
(00BFB25A) C2597_0
(00BFB34D) _run_toplevel_callbacks
(00D3D9E0) TSecureShell::EventSelectLoop
(00D3C8C3) TSecureShell::WaitForData
(00D37379) TSecureShell::Init
(00D36CB9) TSecureShell::Open
(00D89D67) TSFTPFileSystem::Open
(00DC63C3) TTerminal::Reopen
(00DC8A8D) TTerminal::QueryReopen
(00DBD32C) TRobustOperationLoop::TryReopen
(00DE4022) TTerminal::SinkRobust
(00DE3DE0) TTerminal::DoCopyToLocal
(00DB4216) TSFTPFileSystem::CopyToLocal
(00DE392C) TTerminal::CopyToLocal
(000101B4) TCustomScpExplorerForm::ExecuteCopyMoveFileOperation
(00010CA0) TCustomScpExplorerForm::ExecuteFileOperation
(00010E91) TCustomScpExplorerForm::ExecuteFileOperation
(0002300F) TCustomScpExplorerForm::RemoteFileControlFileOperation
(00023445) TCustomScpExplorerForm::RemoteFileControlDDEnd
(0046AA82) Customdirview::TCustomDirView::DDDragDetect
(00C6EF9E) TUnixDirView::DDDragDetect
(00466C9A) Customdirview::TCustomDirView::CNNotify
(0027B89D) Vcl::Controls::TControl::WndProc
(002803E1) Vcl::Controls::TWinControl::WndProc
(002C36BB) Vcl::Comctrls::TCustomListView::WndProc
(00280547) Vcl::Controls::_17076
(002803E1) Vcl::Controls::TWinControl::WndProc
(0027FA28) Vcl::Controls::TWinControl::MainWndProc
(003C7B64) System::Classes::_18201
(0003FE89) USER32.dll
(00036E45) USER32.dll
(00036A45) USER32.dll
(0003A60D) USER32.dll
(00073E7B) ntdll.dll.KiUserCallbackDispatcher
(0003486A) USER32.dll.SendMessageW
(00068881) COMCTL32.DLL
(0019EF20) COMCTL32.DLL
(000A3C35) COMCTL32.DLL
(000648A2) COMCTL32.DLL
(0003FE89) USER32.dll
(00036E45) USER32.dll
(00036522) USER32.dll
(000346C6) USER32.dll.CallWindowProcW
(002804F2) Vcl::Controls::TWinControl::DefaultHandler
(004686E6) Customdirview::TCustomDirView::WMLButtonDown
(002803E1) Vcl::Controls::TWinControl::WndProc
(002C36BB) Vcl::Comctrls::TCustomListView::WndProc
(003C7B64) System::Classes::_18201
(0003FE89) USER32.dll
(00036E45) USER32.dll
(00036522) USER32.dll
(000346C6) USER32.dll.CallWindowProcW
(00079E57) COMCTL32.DLL
(00079EF6) COMCTL32.DLL
(00079CAC) COMCTL32.DLL
(0003FE89) USER32.dll
(00036E45) USER32.dll
(00036522) USER32.dll
(000346C6) USER32.dll.CallWindowProcW
(0049E76B) Dragdrop::TDragDrop::WndMethod
(003C7B64) System::Classes::_18201
(0003FE89) USER32.dll
(00036E45) USER32.dll
(00034BB5) USER32.dll
(0003497B) USER32.dll.DispatchMessageW

(00FC52B1) C5294_3
(00FC688B) _ReThrowException
(00D3748B) TSecureShell::Init
(00D36CB9) TSecureShell::Open
(00D89D67) TSFTPFileSystem::Open
(00DC63C3) TTerminal::Reopen
(00D

The problem happens rarely. I cannot reproduce it.