It is very interesting the phones you guys have aren't automatically rolling back to the next available network; mine does. The phone is never totally out nor do I have to go into any settings to make it work.
It does automatically roll back to 1X. Since Verizon is using eHPRD with the 4G devices when the LTE network goes down eHPRD 3G usually goes with it. That is why you have to go into Modem Settings to get 3G back over the EVDO Rev A. network.