If the code takes a valid series of ICAO waypoints and routes, generates the corresponding ADEXP waypoint list, but then when it uses that to identify the ICAO

If the code takes a valid series of ICAO waypoints and routes, generates the corresponding ADEXP waypoint list, but then when it uses that to identify the ICAO segment that leaves UK airspace it's capable of producing a segment from before when the route enters UK airspace, then that code is wrong, and who knows what other failure modes it has? Maybe it can also produce the wrong segment within British airspace, meaning another flight plan might be processed successfully, but with the system believing it terminates somewhere it doesn't? Maybe it's already been processing all the preceding flight plans wrongly, and this is just the first time when this error has occurred in a way that causes the algorithm to error? Maybe someone's introduced an error in the code or the underlying waypoint mapping database and every flight plan that is coming into the system is being misinterpreted?