Several years ago a NMS feature caused my Android to display: "Unfortunately, Homescreen has stopped - OK" Selecting "OK" may return the homescreen or more likely it will continue in an endless loop with little time to select an APP between notifications. It was solved by turning off an NMS feature - I don't remember which and there are no records at Verizon about a fix.
I recently 11/09/16 did an NMS update and the problem has returned and occurs anytime an app, any app, is closed. Have tried to turn off all NMS feature settings and it still occurs. App Advisor For Google Play is selected off.
If this problem happened a number of years ago, and was not happening since, I would suggest that it had been fixed. Something in the update recently seems to have set this off again for you. I did not see anything like this, so it is possible that something got muddled on your device around the last update. If clearing app data fixed it, it is not the core code, but some data that was saved by the app that somehow got corrupted.
Anyway, keep an eye on things and let us know if the problem returns.
My first suggestion is to restart the phone and test again.
If that does not help, try going into Android Settings - Apps and look for NMS. Delete the app data, restart the phone and test again. You will have to sign back into your Norton Account to regain the full version.
It that does not help, try uninstalling the app, restart the phone and test again.