A weird Flicker

Hi, i have a dvd player linked to a video enhancer stabilizer (a replica of sima product) then to a dvd recorder so then i can back up my dvds that i own and this copys my dvds fine to my dvd recorder in most cases (normal movies that u buy everywhere) but sum dvds i try to copy (mainly adult) dont copy the same and cause a filcker (it looks like 3 short screens that flicker) on the screen. i was wondering if there is a way to stop this and get a clean copy and recording.
Iv tryed bypassing the stabilizer and all it does is lose colour.
Is it because of a particular type of copyright or the way the dvd was written?