Invalid access to memory - TLoginDialog::GenerateButtonImages

<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 5.14.4

Error message:
Invalid access to memory.

Stack trace:
(67F45210)WinSCP.exe
(00083FFF) ntdll.dll
(00071931) ntdll.dll.KiUserExceptionDispatcher
(0087ED86) TLoginDialog::GenerateButtonImages
(0087ECAE) TLoginDialog::InitControls
(0087EF88) TLoginDialog::Init
(0088082F) TLoginDialog::FormShow
(00882D68) TLoginDialog::Dispatch
(00278739) Vcl::Controls::TWinControl::WndProc
(00232C00) Vcl::Forms::TCustomForm::WndProc
(008C4C44) Vclcommon::C2841_0

The problem happens rarely. I cannot reproduce it.