<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 5.17.5

Error message:
メモリのアクセス違反

スタック トレース:
(0041A094) System::UStrCmp
(00087E3F) ntdll.dll
(000732D1) ntdll.dll.KiUserExceptionDispatcher
(00DB0257) std::_Tree<std::_Tmap_traits<System::UnicodeString, int, std::less<System::UnicodeString>, std::allocator<std::pair<const System::UnicodeString, int> >, 0> >::_Lbound
(00DB00E4) TUsage::Inc
(00DB0089) TUsage::Inc
(00DA9DC2) TTerminal::CollectUsage
(000ABC90) TTerminalManager::ConnectActiveTerminal
(000AC60D) TTerminalManager::DoSetActiveTerminal
(000AC35A) TTerminalManager::SetActiveTerminal
(000190B5) TCustomScpExplorerForm::NewSession
(00047984) TNonVisualDataModule::ExplorerActionsExecute
(003E84CC) System::Actions::TContainedActionList::ExecuteAction

The problem happens rarely. I cannot reproduce it.