Evaporator core leaked and replaced. A sign of future problems?

That is a very long job to perform, not surprised it took them a while, especially if the diagnostic process was ongoing. There does not seem to be any technical service bulletins related to this concern. This does not mean it is or isn't a common concern; just means that it's not so common that Ford has published anything about it. Evaporator core failures are not terribly common across most vehicles, that's for sure.