Have you tried contacting Humax support? They can be quite helpful, and if there is any suspicion about the unit they might replace it. They were quick to replace my unit when I had some strange problems.
Having said that, I still occasionally lose padding for no known reason. It is most frustrating when you lose the last five minutes of a show because the mongrel TV stations stick in too many ads.
Another thing - I have found that if you make even the slightest change to the preset recording schedule set by IceTV, all the padding seems to vanish - you have to manually add time.
These units are good when they are working, but can be fussy and glitchy. There is supposed to be a new software update coming out "soon" - hopefully that will fix a couple of issues. PVRs have been around for quite a few years now, it's a mystery to me why they haven't got it right by now.
