I thought I was the only one here that kept my phone on vibrate, so therefore the only one experiencing this problem. Unfortunately, I have not found a fix/work around for it yet, but you are not the only one going through this.
I have been talking to some of the Devs about it (thinking at the time that it was the fault of the app instead of the phone). It may be worth mentioning to your carrier (VZN, Sprint, AT&T etc.) so it eventually gets fixed.