I doubt the swap file is to blame, but if you think it is, simply switch that off and see what happens. I've never had a swapfile active (or needed) on my Vu Duo.
I also never seen hickups in recordings when zapping. You don't have some form of permanent timeshift active by any chance that might interfere?
I agree with you, i will follow your clue about switching off the swap file. At this moment the swap file is using the same hard disk drive used for recordings.
Another related issue is when i zap from one channel to another, in the same satellite, the zapping will take 2 or 3 seconds because it will read something from the hard drive and since the hard drive is in power safe mode, it will wake the hard disk, read something from there and then finally switch the channel. I presume that this issue happens when i zap from channels that are in different transponders. Maybe it will be the picons, i don't know. What i'm sure is when i used BlackHole image with a usb device attached to deal with the swap file this matter doesn't exist.
Do you think that a format in the hard drive could solve this matter?