<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 5.21.1

Error message:
External exception E06D7363

Stack trace:
(0012A922) KERNELBASE.dll.RaiseException
(0008788F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(0004F2D5) SrjdDll.dll
(0003BE4D) SrjdDll.dll
(0003BB8F) SrjdDll.dll

(0012A922) KERNELBASE.dll.RaiseException
(0008788F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(0004F2D5) SrjdDll.dll
(0003BE4D) SrjdDll.dll
(0003BB8F) SrjdDll.dll

(0012A922) KERNELBASE.dll.RaiseException
(0008788F) ntdll.dll
(00073EC1) ntdll.dll.KiUserExceptionDispatcher
(0004F2D5) SrjdDll.dll
(0003BE4D) SrjdDll.dll
(0003BB8F) SrjdDll.dll

Status: other

The problem happens rarely. I cannot reproduce it.