The new Nexus 7 (2013) has been facing GPS and toucch screen issues from the moment ot was released and were supposed to be vanish after the update. But still we have issues in Touch screen of Nexus 7 after the JSS15Q recent software update.
The video below makes it clear that the Touch screen Issues are still not gone after the Software update.
A Statement for the cause of the Problem and why it is not set right with the update is here
The origin of this theory comes from a specific symptom where the tablet doesn't experience any problem while being held or connected to a charger, but erratic behavior and ghost touches start occurring while resting on a flat surface. Again, these are only educated guesses and have not been validated by Google or any third party.
Paul Wilcox administrator from the Google Product Forums confirmed that they are struggling to solve the issue and will also learn about it in future.
Also for people who are facing issues with there Nexus 7 (2013) - your device can be replaced if you are still facing issues after the Update.