RstoxFDA::appendAreaCode was refactored a while back to get rid of rgdal and rgeos dependencies. The new version is a bit stricter and occasionally gives errors with points not being found strictly within polygons. It contains a strict-option to turn this of, but that does not fix it, only replace an error with a warning, leaving some areas as NA. Also the strict-option is turned on in AddStratumStoxLanding (but not in AddStratumStoxBiotic).
Turn off strict in AddStratumStoxLanding
Try to find a way to introduce some tolerance, so that the problem disappears.
RstoxFDA::appendAreaCode was refactored a while back to get rid of rgdal and rgeos dependencies. The new version is a bit stricter and occasionally gives errors with points not being found strictly within polygons. It contains a strict-option to turn this of, but that does not fix it, only replace an error with a warning, leaving some areas as NA. Also the strict-option is turned on in AddStratumStoxLanding (but not in AddStratumStoxBiotic).