When Cisco EzVPN is used in the Network Extension mode to connect to a VPN concentrator with Reverse Route Injection (RRI) enabled, no route is injected for interfaces configured with a 32-bit netmask.
An example for such an interface is a loopback with a /32 IP address, used for remote management through the VPN tunnel.
This problem occurs only when EzVPN is used on the router, and does not affect regular LAN-to-LAN configuration on both sides.
This issue is due to the presence of Cisco bug ID CSCsc66851.
As a workaround, use a netmask that is lower than 32 bits.