Our third party provider/upstream provider has provided the following information about the routing anomaly that impacted some of our IP space from some geographic locations.
"A legacy static route configuration caused traffic to be load-balanced to a new core router being brought up during the scheduled maintenance window. A workaround has been put in place to rectify the issue."
"A maintenance window will be scheduled with the customer (True North ITG) to remove the legacy static route configuration to prevent this from occurring in the future."