Ah, that was a version compatibility issue on my end. If you update to the latest app version (1.58), you'll see the automation. It's just a display issue, the automation is saved and should run. Let me know if that's not the case.
Note that the Tesla app only updates the configuration when the app is started. So if you want to confirm that the configuration has been updated, you'd have to restart the app. But that's just a Tesla app issue -- the configuration changes (and resulting behavior) apply to your Powerwall pretty much immediately. The new Netzero version will also show you the status of automation runs.
Fixed, thanks. It's amazing how the the human brain skips the second one