The not-monitored / monitored state is just telling you how failover is configured. We typically setup ASA to monitor all active interfaces so that if any one goes down a failover event is triggered. (Reference)
Your "show failover state" output explains that the last failover event was due to loss of connectivity on two interfaces on the Primary unit.
Since the current state is "Secondary - Active" and "Primary - Standby Ready", all is well with respect to the ASA failover pair.
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...