Hello Shwu-Jing,
Thanks for your response. Everything was okay with my mobile device location services/status, and the issue was only happening with one survey. Yesterday I had tried removing then re-adding the geopoint but the map still wouldn't load when opened in the app (the coordinates WERE displaying BTW, so i'm sure it was tracking my location), but today I did the same remove/add process again, but also gave the geopoint a different title and placed it in a different location within the survey... and the map finally started loading! I still can't think of any good reason why this would have resolved the issue, but I'm just going to move on for now.
Thanks again,
Gavin