Here are some of the known issues and bugs with 'the Nether Update'

[Windows Central]

There are always some that slip past.
The Nether Update is finally here, and it's rolling out to every supported platform as we speak. Mojang Studios did a commendable job making this update as smooth and stable as possible, but there's always some bugs and issues that slip past, despite the best efforts of everyone involved. They're being dilligent in keeping track of these issues as they attempt to fix them, so we're compiling some of the bigger ones into a handy list for you!

Full story from the WindowsCentral blog...