In the 1st day, 2 hours of use of my Nexus 4 (with 2GB of RAM and 4-core CPU), in 2 situations some default softwares were closed, then reopen but real state was lost. Sometimes this problem happens with only 2 softwares being used at all by the user ! So I take a new Android device, with only default softwares installed, and using Google's softwares I already have this problem. I can reproduce this issue in any Android smartphone, tablet and Mini-PC that I've used so far.