i think i have solved it. It was due to serviceapp. I changed the enigma2 playback from original to serviceapp and player to exteplayer3. Now the channels dont freeze.
Does anyone know the best setting for serviceapp? There is another player gstplayer aswell.
I get similar on odd channels that stop after a few seconds I'm not sure why. As urie said I just install service app and leave settings default then set stream types on IPTV to 5002 and it's fine.
This is a bit of a pain though as vix you can you can set Recordings to convert service types to 1. If you record one of these channels it will just freeze.