Hello Jose
This is an excellent observation. I went into the lab and found that the metric is indeed 2. Doing an initial traceroute from Spoke2 to Spoke1, I found that the hub was the first hop, and Spoke1 was the second hop. When I ran traceroute again, I found that Spoke1 was the first (and only) hop.
This is expected behaviour because with DMVPN phase 2, Spoke2 will check its NHRP cache, and sees that it doesn’t know the NBMA address for Spoke1. It will initially send the packet to the hub along with an NHRP resolution request. But after the first packet goes, Spoke2 will put the NBMA address for Spoke1 in its cache.
The second traceroute works directly, but RIP still measures the metric between spokes at 2, even though the traceroute confirms a single hop. This is the case even after RIP routes are refreshed. Without having found any documentation to confirm this, my feeling is that RIP views the fact that an NHRP lookup has to be requested from the hub as an additional hop even though the actual packets (other than the original one) don’t go through the hub.
I hope this has been helpful!
Laz