Calls/texts don't come in in standby?

[TurboFool]

Okay, this is a completely new problem and it's really pissing me off.

Suddenly, and not always, my phone will NOT alert me to a phone call or text message until I either turn my phone on from standby, or until some sort of alert (like a Task reminder) causes it to turn on. Then suddenly the text message alert or ringtone will start for a half-second and shut off and I'll get the text message and/or alert of a missed call (with a time of that exact minute).

Has anyone else had this happen, and do you know what the cause is? I'm running 2.17 which I flashed to at the beginning of last week.