Do you use picons? And are those installed on the harddisk? You have to install those in flash (plenty of space) or on a USB stick (I have a USB stick in the back of my boxes, for picons and the autobackup data).
It could well be that the picon lookup may also cause the recording hickup. Are you using a standard PLi skin, or some third party skin (possibly with it's own picon renderer)?
in what concern to picons, i'm not sure where they are. Some channels have, others not. I'm using the standard PLI skin.
I've made some corrections in the user settings and the hickups are less notable. They are present when i'm recording one channel and seeing other on same satellite. When i zap to the channel that i'm recording the hickup appear.
Later i will put here prints screens of my config's.
My config for Hispasat satellite: