This doesn't appear to be working today. I know I've received 2 messages today from someone but obviously they are not showing on my account. I'll see if it rectifies itself by tomorrow if not I'll see if I can get it sorted.
I've missed 3 private messages so far today, but it appears to be working now as I've received a message so whoever sent me a pm earlier on I didn't get it and if it's still important send it on again.