This isn't a question. I'm just reporting this in case somebody else comes across this and finds it helpful.
Impacted version is 8.4(10) on 7000 series Nexus.
High-level overview is that we have a partner connected to our 7K (using a Versa Networks router) and exchanging eBGP routes. Our 7K acts as a PE for an internal enterprise MPLS core. The Versa router sent the following extended community: https://datatracker.ietf.org/doc/html/rfc9012#name-routers-mac-extended-commun
The presence of this extended community (for some reason) prevented the 7K from imposing the VPN label and the packet hopped into the target PE's default routing table where it was then discarded by the receiving PE router (essentially destination net unreachable). Our fix was to ask the partner to remove the extended community from their advertisement. After doing that we observed the correct label imposition, and the packet was routed correctly.
