It is usually down to the load on the server, like any other system
you will get glitches during busy periods, such as the last games of the football season
for instance yesterday, when lots of people are viewing.
Sometimes it may be a bit of maintenance too.
Some servers seem to cope better than others. Cable boxes are tied to the KV server
so you can't shop around like on the sat side, but as you know there are no subs
to pay with this box.