You are both right. Prior to Steadfast Ranger I was able to discover a total of 252 locations, too. Of those, 7 locations did not increment the discovered location counter in the journal. So the journal stated only 245 locations were discovered. The seven locations which did not increment the journal's discovered locations counter were: the cabin at Rabbit Grove, Grey Mother's House, Post Office, none of the three Crossroads Houses, and the Draft Dodger's Cabin. I submitted a bug report for this issue.
Just confirmed. Hinterland does pay attention to submitted bug reports of minor nuisances and fixed the Journal's Discovered Locations counter with the Steadfast Ranger release. Thank you, Hinterland support! The 7 locations which did not increment the counter prior to Steadfast Ranger now increment the counter! So if you were counting locations prior to the release, the journal would incorrectly state you discovered only 245 locations (as @peteloud states) and if you are counting locations after the release, the journal will correctly state you discovered 252 locations (as @ajb1978 states).