Android 4.2 Jelly Bean brought quite a few new features to the ASUS Nexus 7, but it also brought a number of bugs along as well. Many users have been having trouble with significant lag (possibly the fault of Google Currents) after the update, although I haven’t had a problem yet, but a smaller subset of users has discovered an even more odd bug. According to at least two separate accounts, when using a secondary user account on the Nexus 7, the homescreen appears to bleed through other fullscreen apps such as games.
As you can see above, the problem makes games nearly unplayable, and certainly looks quite odd. There are different reports as to what causes the bug, but overall most agree that it is common when logged into a second user account. Resetting the tablet sometimes seems to solve the problem, while others have decided that the issue is related to hardware and gotten replacement devices from Google. I haven’t been able to replicate the issue, but it clearly exists. While the reports and details are quite varied, then, there is plenty of evidence to suggest that this is a real problem, and one that Google will hopefully address.
For now, the simple solution for anyone experiencing this problem is to switch to the tablet’s primary user account (and in some cases, disable the other account), but a solution that takes away the new feature really doesn’t do too much good. It seems likely that this problem is simply a software multitasking issue that Google could fix with an update, which would certainly be the best case scenario for both consumers and Google. I doubt either wants another bunch of tablets sent back for repairs.[Reddit 1, 2]