I would probably need Harvest logs to understand what's going on. The strace output seems to point at ZDE which maybe is happening in one of the plugins. But usually ZDE is an indication of something else going wrong.
Can you run the controller in verbose mode for ~20-30 minutes and share the logs with me?
Hi sorry, that I am responding late, a bit though on schedule ...
Not seeing anything useful in the logs you shared, I think I would need the entire log file of the session (from the timestamp you started Harvest in verbose mode), any chance you can share that with me? I'll send you my email address in DM.