This isn’t normal behavior for the app, on either iOS or Android. Yes, every time you fill in a trigger, it gives you another one – IN CASE you want more than one. There will always be an extra trigger not filled in, no matter how many you have. After you fill in the first one, or how many you want, you hit Done, and it takes you back to the main screen of Trigger setup, where you can select the actions for the Trigger.
If you are getting an error when you hit Done after filling in a single trigger, that’s not normal. I can’t make it fail that way, and I’ve tried. So you’re not doing something right, and this problem is not a lack of robustness in the app (there are some flaky things with the Android mobile app, but this isn’t one of them that I know of).
If you still just want it to go away, go into the IDE to delete it. My Locations / List SmartApps / Edit / Uninstall.