I suspect that it may have been removed by the BGP dampening feature in our router. By disabling the feature, the route will stay in our router.
Q1/ My only understanding of the benefit of this feature is to prevent 'unstable' route from flooding to our router, causing a CPU overflow. What's the risk of leaving this off?
things have changed. BGP route dampening is considered harmful. just turn it off. http://www.ripe.net/ripe/docs/ripe-378.html [..] 4.0 Recommendation This Routing Working Group document proposes that with the current implementations of BGP flap damping, the application of flap damping in ISP networks is NOT recommended. The recommendations given in ripe-229 and previous documents [2] are considered obsolete henceforth. If flap damping is implemented, the ISP operating that network will cause side-effects to their customers and the Internet users of their customers' content and services as described in the previous sections. These side-effects would quite likely be worse than the impact caused by simply not running flap damping at all. [..]