Interesting Routing Issue I've Noticed on IOS-XR

Hey All.

This is the second time i've seen this, and i'm not sure why it's happening so i'm hoping someone else came across this. And I don't know if it's specific to just IOS-XR (9010 platform for what it's worth); i'm sure it's not.

In short, I have a prefix that when you do a show route ipv6 <prefix> it says the proper exiting interface along with where it's learning it from. When you do a traceroute though, it goes out a completely different interface...like, that interface is a totally different environment. That prefix or even the agg it belongs to has no bearing within this segregated network. The way we fixed it before was we shut down that interface, brought it back up, and routing was fine after that (about 3 months ago).

This is happening on a different router so the first issue is still resolved, but i'd like to know HOW to fix this properly and WHY it's happening. I suspect something in the FIB, but I don't know how to look that up currently in the ASR. I will google that right now, but if anyone has any info, by all means please share.

Thanks.