I am experiencing some strange behaviour after upgrading from the 3.2 to the 4.0 Network versions. I have a backend set up where php sends SOAP requests to the zimbra server. In 3.2 this worked with no problems at all. After upgrading to version 4.0, it seems every 7th request is not received (or is ignored by the Zimbra Server) and is generating "curl_exec error 7 couldn't connect to host" errors. If I retry, it goes through without a problem for another 7 tries before hitting the same error.
I believe this must be a Zimbra issue since it was working fine in the previous version and this only started with the upgrade. Is there some throttling mechanism in place with the new version that could be causing this?