I have a Samsung DVD recorder that does the same thing, albeit not very badly. I think it's the DVD recorder that's at fault- when it's switched on, it is processing the analogue signal that it's being fed, and whilst you'd hope that it would output an exact copy of what was being input, it's...
I have a Panasonic DMRES15 DVD recorder that for two years has been connected to a Sky+ box and a TV. Initially the TV was an old Toshiba 28" CRT model, but as soon as I upgraded to an HD ready set a few months ago I noticed a problem with picture quality when the Sky signal is being viewed...