the solution is simple. It seems, you are having the same or an overlapping subnet on the inside and outside interface. The dissappeared routes are hostroutes. If you are adding an route for an overlapping subnet, the devices thinks, this will be for the host routes too, an kick them for the config. After that, you can add them again. But, you shouldn't have overlapping subnets at different interfaces. It's dirty. Wondering why it's working....
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...