In the topology, I have all internal Peers (Site A,B,C) in AS 65002. these peers are connected through the transit ATT router (using AS number 1500 as in topology). The problem is, site C can ping only to the advertised networks from site A (10.2.254.9) and site B(10.11.254.9). It doesn't see the network segment between site A and site B i.e. the 10.10.254.x network even thou these are all being advertised. However, the ATT router could see it with no issues.
What am I missing?