A new version of the Trail Blazer Basecamp app is available for iOS (version 2.1.58).  This version includes an updated mapping engine.  You can download it here: https://apps.apple.com/us/app/trail-blazer-basecamp/id1219460381

Note: if your device is on automatic updates, you likely have the latest version.  If you experience an issue where the map doesn't display correctly, you'll need to offload and reinstall the application to clear your cache.