Hello David
In an IPv6 MPLS VPN scenario with TE enabled, several specific configurations are necessary to ensure that IPv6 traffic can be sent between CEs. If IPv6 routes are exchanged through the VRF without TE but traffic is not flowing when TE is enabled, it indicates that there may be missing or incorrect configurations related to MPLS TE for IPv6.
One question I do have, is what do you mean when you say “if IPv6 traffic cannot be sent between CEs?” What is preventing the IPv6 traffic?
In order to be able to further help you in this scenario, let us know a little bit more about your topology, what you are trying to achieve, and where the network is not behaving as expected so we can help you further.
I hope this has been helpful!
Laz