Invalid access to memory - TFrameAnimation::Repaint

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WinSCP 5.11.1

Error message:
Invalid access to memory.

Stack trace:
(0007565E) TFrameAnimation::Repaint
(000851DF) ntdll.dll
(00073161) ntdll.dll.KiUserExceptionDispatcher
(007E7C0B) TFileFindDialog::StartStopButtonClick
(00257BA1) Vcl::Controls::TWinControl::WndProc
(001BFD30) Vcl::Stdctrls::TButtonControl::WndProc
(00257D07) Vcl::Controls::_17076
(00257BA1) Vcl::Controls::TWinControl::WndProc
(00212068) Vcl::Forms::TCustomForm::WndProc

The problem happens rarely. I cannot reproduce it.