Out of memory

<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 5.17.10

Error message:
Out of memory

Stack trace:
(00419BA6)
(00419BA6)
(003A47A7)
(0023A15C)
(00DDD6B8)
(0027AD15)
(002351DC)

Status: unknown_rel_addr

The problem happens rarely. I cannot reproduce it.