Sorry, not reply in time, pls kindly check below answer;
1. About delay setting, please edit in the Activity, Edit---Startup settings, you can add the delay and move to the appropriate location.
2. Per the crash problem, please try to uninstall the app, and then re-download the app from the app store/ google play. then add the Activity again to see if it is OK.
Note: The data of the device exists on the Hub, reinstalling the app will not affect the information already configured in the hub.