I had multiple SFTP sessions opened, I "alt-tabbed" to the app and hit CTRL + R.

WinSCP 5.15.9

Error message:
Invalid access to memory.

Stack trace:
(00916C6x) __odtbl__ TEditorForm::CheckFileSize
(00087D7F) ntdll.dll
(00073221) ntdll.dll.KiUserExceptionDispatcher
(000B6BAB) Vcl::Styles::_16523
(000B6C6F) Vcl::Styles::_16524
(0003DC8F) TScpCommanderForm::SynchronizeBrowsingRemote
(003E7958) Dirview::TDirView::DDMenuPopup
(001C64F6) Vcl::Graphics::TBitmap::SetTransparentColor
(004A1446) Jclpeimage::_16658

The problem happens rarely. I cannot reproduce it.