Copie de fichiers vers le coté distant échouée

<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 5.15.5

Error message:
Copie de fichiers vers le coté distant échouée.

Accès mémoire invalide.

Status: not_matched

The problem happens rarely. I cannot reproduce it.