@ramadhanmzikri: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

<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 5.21.6

Error message:
Invalid access to memory.

Stack trace:
(004DF06B) Tbxextitems::TTBXEditItem::
(00FDF74E) C5412_0
(00FE17B6) ____ExceptionHandler
(00FDE570) __ExceptionHandler
(00097C6F) ntdll.dll
(00077BA1) ntdll.dll.KiUserExceptionDispatcher
(00D0288F) TTerminalQueue::GetIsEmpty
(00009B73) TCustomScpExplorerForm::AddQueueItem
(000166FB) TCustomScpExplorerForm::ExecutedFileChanged
(00077C91) TEditorManager::CheckFileChange
(00075A31) TEditorManager::Check
(0001A089) TCustomScpExplorerForm::Idle
(0004DDFF) TNonVisualDataModule::DoIdle
(0004DDBC) TNonVisualDataModule::SessionIdleTimerTimer
(003C9C14) System::Classes::_18201
(00031331) USER32.dll
(000220E1) USER32.dll
(000209A0) USER32.dll
(000204EB) USER32.dll.DispatchMessageW

(00FDFDB9) C5412_0
(00FE1393) _ReThrowException
(00077CD1) TEditorManager::CheckFileChange
(00075A31) TEditorManager::Check
(0001A089) TCustomScpExplorerForm::Idle
(0004DDFF) TNonVisualDataModule::DoIdle
(0004DDBC) TNonVisualDataModule::SessionIdleTimerTimer
(003C9C14) System::Classes::_18201
(00031331) USER32.dll
(000220E1) USER32.dll
(000209A0) USER32.dll
(000204EB) USER32.dll.DispatchMessageW

I know how to reproduce the problem or the problem happens frequently enough. I wish to be contacted by the WinSCP team to help resolving the problem.