class PushNotification.send calls Mobile App Push Notification which calls apple_sendNotification.
In line 38-42 we have
If (Length($cmdPush_err)>0)
LOG EVENT(Into 4D debug message; $cmdPush_err)
End if
but, we don't return $cmdPush_err up the chain, so the PushNotification.result property is never set with the error, etc.
I ran into this issue, today. I got warnings, including a warning that a push notification was not sent (but no error), and I did not get a reason returned, either.