In December of last year, I was able to get an mmpk working on the Android version of ArcGIS Explorer. The process included creating the map in ArcGIS Pro, uploading it to ArcGIS Online services, and then opening the Explorer app on Android and downloading it.
This time around there are no errors in the pre-upload analysis, the thumbnail even displays on both the website and in the app. However, after the map is downloaded to my Android device, trying to open it changes the name to "Invalid Map" and breaks the thumbnail.
I have tried reinstalling the app/restarting the phone, updating ArcGIS Pro/restarting the PC, and numerous different configurations of map files (Groups, no groups, various different layer types).
Has something changed in the ArcGIS Explorer app to cause this, or could I be missing something obvious?