For what it's worth, I too have experienced the problem. I'll try to keep an eye out when it happens again to see if I can replicate it. I superstitiously attributed it to my phone being nearly out of memory or having too many apps open. No real support for that thought as I didn't check my memory at the time.
P.S. Nic, if you don't recognize the handle, this is Chris Rock. We've been chatting about my local event and the Maritime Mega.