are you sure we execute this? because it looks like my gecko redirects to  `/message-sms-received.html` or something, because:
* I launch the SMS app
* I press home
* I send a SMS to this device
* I wait the notification to be displayed
* I run `adb shell b2g-ps` and I see the Messages app has been closed

And then:

* I launch the SMS app
* I press home
* I run `adb shell b2g-ps` and note the PID for the Messages app
* I send a MMS to this device ("autodownload" is disabled)
* I wait that I see some network activity, but I don't see any notification
* longpressing home show me a blank page for Messages
* `adb shell b2g-ps` shows the PID is the same

So basically the same behavior than https://github.com/mozilla-b2g/gaia/pull/18394/files#r12302602

Is it possible that my gecko is too old (it's clearly possible, it's maybe 1 week old, and from the v1.3 branch, not v1.3t; note that I use a Inari to review) ?