After a very long wait for Windows Phone 7.8 for users of legacy Windows Phone hardware, the update finally started rolling out for many (but not all) supported handsets. The new update brings resizable tiles and some other WP8-style improvements, but apparently brings a new bug with it.
Reports are starting come in that the update is causing a glitch for some users where it effectively locks up Live Tiles and prevents them for updating dynamically. The live tile notifications in Windows Phone is one of the most recognized and crucial features for Windows Phone, so this is certainly a pretty big deal for some users.
The good news is that some users are reporting success fixing the glitch by resetting the phone and reinstalling apps, but that’s a lot of work when all is said and done. While this is always a possibility, if it sounds like too much– just be patient. Microsoft is already aware of the situation and is looking into a fix, so hopefully this won’t be a problem much longer.
[ source ]