The router they were running did not have an IGP configured. It's hard for
me to imagine how a misconfiguration could cause what occurred, but I'm
still waiting to hear what the outcome is/was.
The router only had an eBGP session up to another BLN; even if one of them
was reconfigured accidentally for BGP3, the AS-PATH truncation should not
MAI has been very stable across their MAE sessions - and has been using a BLN
for their MAE router for many moons now.
Of course misconfigurations can happen, but the MAI people are not without
clue. Of course, my traditional point about Bay vs. Cisco is that it's
easier to find people experienced with configuration gotchas for Ciscos
because of the large crowd of Cisco-experienced individuals out there.
Anyway, sorry I raised hackles.