Not until we understand what needs to be fixed.
For the moment your description is rather confusing and seems to describe at least two problems:
- displaying the map image;
- displaying the assignments markers on the map.
Whether they are somehow related to each other or not, is anybody’s guess. How are 60 persons related to this? Do they ALL have the same problem? Do they all use the SAME map file?
Shooting with my eyes closed, check if the tablet contains an invalid map file, which is loaded by default when the map view is switched to. If it is somehow corrupt, it may derail that whole view.
If that is fruitless, test with a blank device in a controlled environment by making 1 assignment and passing 1 map file to that device.
It wouldn’t hurt to mention in the description the version of the Interviewer App and the format and process of generation of the digital map file, process of transfer of the map file to the device, etc. If you have a fieldworker manual describing the process, include the link to it.