try installing this hotfix on the vm's before cloning if they are windows 2008 r2....there is a bug that causes the nic to regenerate each time its moved...I found that on my vm's if I install it on an existing running vm it reverts it back to the very first nic in the system (vs giving me the local area network #2 or #3,etc...
Windows may fail to boot from an iSCSI drive if networking hardware is changed