The image erase button in the iOS version of the app send the OS RESET (Group 0, Command 5) command, instead of the IMG ERASE (Group 1, Command 5) command.
The Android version of the app does not have the same issue.
Upon clicking "Erase", the connected device reboots.
After adding additional debug information, it is easy to see why:
SMP CMD: GRP: 0 ID: 5 OP: 2 ... Immediately RC: 0
Compared to the Android app:
SMP CMD: GRP: 1 ID: 5 OP: 2 ... Delay of ~2 seconds RC: 0
iOS app version: 2.7.10
Android app version: 4.28.1