<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 5.15.2

Error message:
Invalid access to memory.

Stack trace:
(004176D3) System::DoneExcept
(000823CF) ntdll.dll
(0006FF4A) ntdll.dll.KiUserExceptionDispatcher
(003A3BA8) System::Classes::_18201
(0002C311) USER32.dll
(0000D8D5) USER32.dll
(0000D22F) USER32.dll
(0000CFDB) USER32.dll.DispatchMessageW

(004172C0) System::HandleAnyException
(000823CF) ntdll.dll
(0006FF4A) ntdll.dll.KiUserExceptionDispatcher
(003A3BA8) System::Classes::_18201
(0002C311) USER32.dll
(0000D8D5) USER32.dll
(0000D22F) USER32.dll
(0000CFDB) USER32.dll.DispatchMessageW

Status: all_insignificant

The problem happens rarely. I cannot reproduce it.