Companion App: camera icon doesn't actually save pictures

What Works: When running Zwift on a Windows laptop and running the Companion app on an Android phone, clicking the “take picture” icon on the Companion in-game map saves a screenshot both on the laptop (in …/Pictures/Zwift) and on the phone (in a gallery album titled Pictures).

What Doesn’t Work: When running Zwift on an Android tablet and running the Companion app on an Android phone, clicking the “take picture” icon on the Companion in-game map makes the tablet screen flash and you hear the little camera-shutter sound, but no image is actually saved anywhere.

What am I missing? Any/all help would be appreciated.