Invalid access to memory

Winscp was already running for some hours.
There was no user action at all, when it crashed.

WinSCP 5.7

Error message:
Invalid access to memory.

Stack trace:
[00DD8703]
[015B05DE]
[015B2646]
[015AF5C0]
[7742B61F] ntdll.dll
[77418E7A] ntdll.dll.KiUserExceptionDispatcher
[00E0DCBB]
[00DD887E]
[014DC4BD]
[014175A7]
[014F09F9]
[00DE085D]
[00DE1462]
[00DE1A42]
[00DE6FBD]
[00DE6E92]

[015B0C49]
[015B2223]
[014173FC]
[014F09F9]
[00DE085D]
[00DE1462]
[00DE1A42]
[00DE6FBD]
[00DE6E92]

[015B0C49]
[015B2223]
[00DE09E5]
[00DE1462]
[00DE1A42]
[00DE6FBD]
[00DE6E92]

Status: symbol_unknown

The problem happens rarely. I cannot reproduce it.