You don't say if these were downlinked routes or manually entered into the FMS. However, I find it difficult to believe they were downlinked, because the course & distance would have flagged the error. Besides,
AFAIK, N5050 is not a valid format in the first place; the only valid formats I know of would be 50N50 (N50W150) or 5050N (N50W050).
It would have been better to enter 4550N (N45W050). It would have been even better to enter the longhand N45W050. Better yet would be to check the waypoint and route in the FMS before entering oceanic airspace.
I think there's a bit of a problem with that report...