I have repeating WeekDay alarms setup on my SN account, to play on my boom.  I noticed that for the first week they went off with no errors.  On the 2nd week, the alarms went off, but no sound came out of them.

The following is my alarm setup

I.E. 
All Alarms On: Vol 6: Fade in YES: Repeat YES: 
Alarm 1 - M-F: 7:00AM: RadioTime - 88.5 KQED: (http://opml.radiotime.com/StationPlaylist.axd?stationId=34804&username=sampletime&Location=z94544)

ALarm 2 - M-F: 8:00AM: Sound Effects > Sub Alert

Alarm 3 - M-F: 7:30AM: Slacker > Teen Rock: (slacker://stations/4595820/500.mp3)

Alarm 4 - Everyday: 8:15AM: Sound Effects > Ambulance

The behavior is that the alarm will trigger, but no sound will be comming out of the boom.  The volume is at 60 (as set) I can move the volume up or down, but still no sound.  If I stop the alarm (power) and then press Play, the stream will start to play normally (at the stopped volume)

To get the alarms to work again, I have to remove them all from SN, then add them back in.