I'm currently investigating a big log issue to, could it be that this bug was also in version 5.9.3 ? if that's the case when will 5.14 will be public availible?
First, what this thread is about is not a bug.
Second, "big log issue" is pretty vague. What specific log entries make the log big? More verbose logging of synchronization was introduced in WinSCP 5.0.8.
We have no plans for release of 5.14 yet.