My Lumia 920 did not show text message notification for few days.
I only know there is a new message when I click into the messaging threads list.
I have checked my settings and I can't find any solution.
Reboot. Other weird random things happen every so often. Rebooting is the common fix. I know, annoying, but for v 1.0 product its expected. The iPhone never really rocked a solid OS for the first few years either.
I noticed I am having the same problem. by reboot do you mean the "reset your phone" option under settings or just a power off/on? I would rather not have to reset my phone and lose my info but the typical power cycle isnt doing the trick