Twonky with Panasonic mp4 stops playing after some seconds

My Panasonic Viera starts playing mp4 files from Twonky but stops after some seconds (differs 18 seconds - 38 seconds).

I was running version 6.x now 7.x. Problems still the same.

The Client Profile is recognized correctly.

Do I have to do a quirk? Is there a list of all quirks?

Thanks for helping.