That audio is computer-generated and not in vanilla WK – it’s accidentally added by the Advanced Context Sentence script because the script thinks these are also context sentences. If you switch to a different Pattern of Use and then back to the initially selected one you will notice that the script does not re-apply its modifications and the examples stay in their vanilla WK appearance.
Furthermore, the original Advanced Context Sentence script is not maintained anymore, but there is a newer version:
However, this version “fixes” the “problem” described above and only changes the context sentences without affecting the Common Word Combinations section. If you are using this bug as a feature, it might be better to not switch to the newer version.