There are at least a couple of us having the same notification issue with email alerts (see Weird Notification Problem).
It seems like the “printf” output (i.e. message body) isn’t making it into the message delivery system (sendmail in my case, sms client in yours).
This is an issue with both 3.0.6 and 3.1.0 (I upgraded to testing in hopes it would help - no change).
Anyone else have any thoughts on this?