iMessage Notifications not working when there are other Notifications

Since 18.5, I have been experiencing an issue where I will look at my phone for something and notice I have several iMessage/Text Messages that I received but the notification sound never went off nor did the screen ever light up to notify me.

I have went through every trouble shooting step there is and I even completely erased the phone and started as a "new iPhone" without using a backup and the problem still existed.

So I went to an Apple store for some help and that is where we noticed something odd. If I have notifications in the notification center from any other app (email, social, etc) that I haven't checked/cleared out and I am sent a iMessage/Text, I am not notified of that message.

However, if I completely clear out all notifications from notification center and then I receive an iMessage/Text, the screen will light up and the sound will come through and as long as I don't receive any other notifications from a different app, the iMessage notification will continue to ring. I have it currently set to remind me 3 times.

I have seen several posts of others having iMessage notification issues but haven't seen this particular issue raised yet.

Anyone else experiencing this issue?