There is some legacy stuff in the box that does get sorted out now and then. I noted a few when first getting into the RNP-AR coding. Smiths box would not allow an airport rwy endpoint over 10,000 feet. We were specifically always using flyby waypoints, even on tangent, tangent legs. There was a memorable waypoint which was erroneously coded flyover, when the ac passed over they waypoint, it porpused down about 300 feet and leveled off. Turns out, there was a legacy item the code looked up (in the sequence) that looked back to a simple radius of the Earth that was coded in. The ac went from the GPS geiod altitude to the simple radius altitude on the lookup.
Took a while to debug that one, but when you actually look through all of the code, you see all kinds of crap. No one is sure where/when to fix it, because not sure all of the myriad of sequencing possibilities in tracing the code.
Note: a long while back, there was a question on submerging the box in fresh water. Anything that has been submerged need to be soaked in fresh water, as the salt is so corrosive. Artefacts such as cannon from shipwrecks are soaked for years.