[c-nsp] Why can't I NAT the same address in different VRFs?

[Gary Roberton]

Anyone help me understand why I can't NAT the same address in two different
VRFS according to the config below;

!!
ip cef
!
ip vrf one
 rd 1:1
 route-target export 1:1
 route-target import 1:1
!
ip vrf two
 rd 2:2
 route-target export 2:2
 route-target import 2:2
!
interface FastEthernet0/0
 no ip address
!
interface FastEthernet0/0.1
 encapsulation dot1Q 1 native
 ip vrf forwarding one
 ip address 10.0.0.1 255.0.0.0
 ip nat inside
 no snmp trap link-status
!
interface FastEthernet0/0.2
 encapsulation dot1Q 2
 ip vrf forwarding two
 ip address 10.0.0.1 255.0.0.0
 ip nat inside
 no snmp trap link-status
!
interface FastEthernet0/1
 no ip address
!
interface FastEthernet0/1.1
 encapsulation dot1Q 1 native
 ip vrf forwarding one
 ip address 217.0.0.1 255.0.0.0
 ip nat outside
 no snmp trap link-status
!
interface FastEthernet0/1.2
 encapsulation dot1Q 2
 ip vrf forwarding two
 ip address 217.0.0.1 255.0.0.0
 ip nat outside
 no snmp trap link-status
!
ip nat source static 217.1.1.1 10.0.0.5 vrf one
!
Router(config)#ip nat source static 217.1.1.1 10.0.0.5 vrf two
% 217.1.1.1 already mapped (217.1.1.1 -> 10.0.0.5)
Router(config)#

Thanks