Small flicker - any ideas

I am getting a small flicker at the top of some of my encodes using the following script. Any suggestions as to what might be causing the flickering? loadplugin("mpeg2dec.dll") #loadplugin("vobsub.dll") loadplugin("decomb.dll") LoadPlugin("c:\filters\convolution3d.dll") mpeg2source("Fushigi Yugi 7 of 7.d2v") crop(4,2,696,476) Telecide(guide=1,gthresh=50,chroma=true,threshold=10) Decimate() #vobsub("X:\path\to\vts_01_0") Convolution3d (preset="animeHQ") bicubicresize(544,416,0,0.75)

again, need help 

Well no one answered so maybe more information will help. I don't see any problem in newer anime titles. The older the title the more little glitches I get in the picture. It is rather like seeing something on a projecter and you get a hint of a flaw in a picture after it is watched a couple of times. You can still watch the movie, and even get used to the flickers, but why do so. The flickers are not on the original source material. I am updating all of my filters tonight to make sure they are the latest and greatest. I am mostly encoding anime, though I do make the occasional movie. I like to keep backups of all my stuff as some friends are rather careless with my stuff. Any help that anyone can suggest is appreciated.