As far as I know, for Windows DNS, unlike BIND, ttl 0 doesn't work as we expected.Actual minimum ttl is likely to be ttl1.We experienced this problem at multiple site which uses Windows DNS.  So if multiple request for SmartConnectZone happen in 1 second, Windows DNS use and reply same IP to clients.
HI,We use smartconnect in our Onefs 7.1 to balance our load on all 70 ESXi server. We use  24 nfs mounts on each servers. when we boot the ESXi server, the mount is to fast and we received only a few differents adress for the NFS mount. It look like if we ask the smartConnect for an adress true a Windows 2k8 DNS delagation, we receive the same adress if we ask for 2 adress in the same second. TTL is set to 0.  We have connect to the EMC formation LAB and it give us the same problem at your site !!!!  Any work aroud exist for this?
SmartConnect problem with Win2k8 DNS delegation