I've added a signature as per your request.
When it goes about channels that are freezing the list would be pretty long as it's all channels that are exclusive to Cyfra+ & N (nc+) such as Canal+ HD, Canal+ Sport HD, nsport HD, Minimini+ HD etc.
Channels like TVN, TVP HD, TVP1 & TVP2 etc. are fine when I'm only connected to Cyfrowy Polsat but when I connect to Cyfra+ and/or N they also start freezing.
I've checked all my network settings, tried different router but that not solved the problem.
Any help would be really appreciated !