Messages not showing up

[cafcross]

Been having this problem for a couple of weeks now. I'll receive a text message but my phone won't go off, and won't show me I have a message on the lock screen. However, when I unlock, the notification icon is on the message app icon. I'm using the latest software. It's happened to my missus a few times too, again she's on the latest software, and we're both using 4S but on different networks.

Has this happened to anyone else?

 

[Adam.]

Got do not disturb mode on?

Is "view in lock screen" shown for messages in notifications > messages?

 

[cafcross]

Nope, everything is fine regarding those options. It's not happening all the time, only now and again.