An issue after getting a new mobile phone

I have recently purchased a new android phone and I’m experiencing a problem. Some lessons load with the audio as normal but other lessons simply load the audio without the texts to accompany it. My phone is currently using the most up-to-date software that being Android version 5.0. I also believe that the LingQ app is version 4.0 or technically speaking 3.9.2.

Is it worth exchanging my phone for another one of the same kind?

Hi Tourminator,
Can you please try to reinstall the app and check if that will help? I am using Android 4.3 version and I’ve never experienced that issue.