Hello,
I just upgraded to last version and my alerting stopped working.
When I click preview in alert rules I see that not all series are loaded. For example I click and I see 2, after a few seconds I click again on preview, I see 6. Eventually it willload all and try to trigger the alert but it never manages.
Not sur eif I explained correctly 
Thanks!
For testing I put on 1m, which in v10 always sent the notification correctly every 5 minutes.