Able to learn mac on arp but cannot ping

From router, I cant ping the peer address. Though I can learn the mac from switch and resolve using arp?

This is just a point-to-point connection.

Diagram: RT1---SWC4500(g2/10)---RT2

Also from switch Im seeing that peer IP has multiple vlan tag? Do you think i affect the layer 3 reachability?

SW#sh mac address-table interface g2/10

Unicast Entries

vlan mac address type protocols port

---------+---------------+--------+---------------------+-------------------------

600 5c5e.abd2.3561 dynamic ip,ipx,assigned,other GigabitEthernet2/10

621 5c5e.abd2.3561 dynamic ip,ipx,assigned,other GigabitEthernet2/10

RT1#sh arp | i 1.1.1.1

1.1.1.1 - d867.d929.c744 Interface ARPA Bundle-Ether12.621

1.1.1.2 00:00:06 5c5e.abd2.3561 Dynamic ARPA Bundle-Ether12.621

What would be the cause possible of IP reachability issue?

Thanks