When I enter a lesson (any lesson) both in Finnish and in Swedish, then I can listen to the first sentence I want to (whichever sentence that is). After that neither the shortcut (<a>) nor the button for audio works on other sentences. The only way for me to listen to the audio is to edit the sentence and press the play button in the edit sentence mode. If I return to the original sentence I listened to, then I can listen to that sentence again, but all the following sentences do no longer play audio.

If I refresh, or re-enter the lesson, I can again listen to *one sentence*. After that all sentences following refuse to play the audio, unless I edit that sentence.