Hmm Wonder if you should try a later version (unless you're on latest). I made some changes a while back as I used to default the start up stream to 60 mins, but found that 3 seconds worked better.

And recently while having my lounge painted, I ended up using the channel for our day to day tv watching....and it was on one tv channel for about 2 - 3 hours without dropping. So I'm not sure where you 20 mins is coming from....ah I think I see now, you're still using the one that has the recordings view? I took that out quite a while ago as it wasn't working (stream wouldn't start), so I just have it as live tv only now.