it happens to me too GR, all i can say is check your general settings and before you hit "send" check it has subscribe to topic ticked. I find also if its a "sticky" or "announcement" I sometimes don't get those. As Admin I'm supposed to be alerted when someone joins and I get every 3rd or 4th person notification sent to me. I think its really some sort of glitch with the actual server
Remember - - - 'STRESSED' spelt backwards! is 'DESSERTS'