Overlap. The dialed number is matching on a pattern where the number could be longer than what was dialed. If this is a non-NANP (so international) number then the only real mediation is to shorten the T302 timer under Service - Service Parameters Cisco CallManager Service - Advanced T302 timer. Set it down to something more acceptable but understand this interdigit timer affects all calls in the cluster.
If this is to NANP destinations then you should construct your dial plan and patterns so that there is no overlap. The Route Plan Report helps when looking for overlapping patterns.
Don