Experienced this for the first time on Monday. I had been texting back and forth while talking on the phone, and all of a sudden my sent texts were no longer showing up. Nor was I receiving any replies. After my phone call ended, I did a luna restart and then a full restart, neither of which remedied the problem. After about 20 minutes, all the texts I'd sent/received showed up all at once. I called the person I was texting and they had received my texts when I sent them and replied, it's just that neither one was showing up on my phone.
Is this pretty common?