I've tried this on real devices and also in the simulator with the exact same anomaly. Listen to the strange sound she adds to the end of the sentence.
<speak> This recipe has also been sent to your Alexa mobile app. </speak>
What's really odd is that I've tried removing or changing random words in that sentence and whenever I do, the strange sound always goes away. For example, remove the word "mobile" or change "recipe" to "thing" or change "This" to "The" and she finishes the sentence normally so it seems to be something very specific to this exact sentence.