I have a new PE with the ermine update and it has been having problems going into hibernation- sometimes when I fold it shut it hibernates and sometimes it doesn't. The power switch always works and it has never had a problem coming out of hibernation.

I have wi-fi turned on, and set to sleep when the screen goes off.

I have very few apps loaded on the device and when I look at "running processes" I don't see anything related to any of those apps. Any ideas?