Update: a 1.2.1 hot fix was released to the App Store that resolves this issue. If you are experiencing this problem, please update your app to at least 1.2.1.
Our 1.2.0 release introduced a new bug that is causing characters to repeat and skip when you type on the Cover, Impact, Video, and Email pages. We are working to get a patch released as soon as possible.
In the meantime, the best workaround (albeit not perfect) is to copy your text from another application (such as "Notes") and paste it into the text areas. Duplication of this text still occurs, but removing the extra text is much faster than trying to type from scratch within the app. See the video below for an example: