Accès mémoire invalide

<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

Error message:
Accès mémoire invalide.

Trace de la pile :
(FFFFF044)
(000689FA)ntdll.dll
(00068E5E)ntdll.dll
(0006B2C9)ntdll.dll
(0006B547)ntdll.dll

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.