BGP link-local nexthops are broken on passive side of BGP session [bisected]

[eqvinox]

Since commit 0c3a70c64430448c43fe12bf0ac044488352697c, with a config like this:

     neighbor fe80::1234 remote-as external
     neighbor fe80::1234 interface eth0
     neighbor fe80::1234 capability extended-nexthop

It gets (when trying to install an IPv4 route with IPv6 nexthop, but it likely affects pure IPv6 too):

W3X54-30BTE	debug	Allocated bnc fe80::fc01:ff:febc:300/128(2)(0)(VRF default) peer 0x0	
VKMV1-4Y773	debug	bgp_update(0.0.0.0): NH unresolved

https://aurora.nox.tf/tmp/topotato/reportato/test_bgp_ecmp_enhe_py__BGP_Unnumbered_ECMP.html#,log=ewnid, (currently cleaning up test to push it out)

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[famfo]

This is still an issue as of version 10.0.