BGP may or may not still be involved. BGP itself has no real facility for dealing with circuit congestion. So, I am willing to bet that dynamic routing was ce

BGP may or may not still be involved. BGP itself has no real facility for dealing with circuit congestion. So, I am willing to bet that dynamic routing was certainly in place, but the secondary/eBGP multipath destinations were full when the primary path went down. And that necessitates manual action in instances where you aren't doing MPLS-TE, or don't have enough standby capacity, or both.