Only a details analysis of the conversation (and it's timings)between the HB-1000S and the broadcasters servers will show where the problems lies. I presume the broadcaster and STB manufactures have a shared specification of how this should work. It may be the case that the spec needs enhancement or that tiny differences in timing cause the problem.
The problem is known (by freesat additionally I think by Humax and also I guess by channel 5 (in spite of their emails)) and I presume being worked on.
