Here’s how to close out of the Bustle app and restart. This refreshes the app and can help resolve small issues.
For new iPads that no longer have the physical button.
From the Home Screen, swipe up from the bottom of the screen and pause in the middle of the screen.
Swipe right or left to find the app that you want to close.
Swipe up on the app's preview to close the app.
more on that from Apple, here.
Press the Bustle icon again to reopen the app.
For older iPads that still have the home button:
Click the iPad’s Home button on the iPad to display the main screen.
Press the Home button twice again quickly to bring up the list of open apps. Scroll across (if needed) and locate the minimised Bustle screen. Swipe upwards on the minimised Bustle screen to properly close out of the app (as below).
Press the Bustle icon again to reopen the app.