GPX Viewer

Hello! We use GPX viewer pro heavily as a team of biological consultants in Southern California. GPX viewer pro, and making GPX files from excel files every evening, allows for easy coordination. Our iPhone users, however, are experiencing an issue. The GPX import appears to have only one icon type and colour. Our import works perfectly on Android devices, showing multiple colours and icon types for different team members. Is this a native iPhone issue? Or is this a settings issue? Is this a bug? This renders GPX viewer pro nearly useless for our iPhone users. We are struggling to find a suitable replacement for them.