Any known reasons for WWW requests to get stuck on android?

We are currently working on a project where a lot of assets (textures, animations, text and data) is streamed in through WWW requests during game play, but we've found that while it works fine on PC it does not on Android. Just after a couple of successful WWW requests they stop working and every WWW request thereafter will just stop working, they never return an error or anything and www.isDone is forever false.

I've tried to create a test project where I just run the download code where the problem occurs, but it works fine - which leads me to believe that something else in my project is affecting the WWW requests indirectly. And that is why I ask the question: Is there any known reasons for WWW requests to get stuck, specifically on android, where otherwise it would not? For example does multiple simultaneous requests affect it at all?

Thanks.

PS: We are still on Unity 4.2!