There are fields in the drill-down hierarchies of the Jobs assigned to the mobile user that they do not have access to in their security profile. If the field is a relationship field, they'll also need object level access to the parent object in that relationship.
- Go the Setup > Objects.
- Click on the object name that the field belongs to.
- Click on the field.
- Click on Set Field-Level Security.
- Ensure the checkbox "visible" next to the user profile is marked as below.
If the above doesn't work in alleviating the error, please contact us at email@example.com.