I would say it's definitely depend on the theme, not other plugins being incompatible with one another. I just again tested it with zero plugins activated, but the main theme I showed you and the streaking is present in IE.
If it can be narrowed down to the themes (which seems logical right now after my and your testing), could we trouble shoot and see if the problem can be located?
We know it works on your website: dittynewsticker.com and it works with wordpress default themes.
We also know that scrolling speeds don't change the streaking (I tested this).
Is it possible that the theme's js code is clashing in random browsers?
Have you had a chance to experiment with different scrolling options as you mentioned? Any luck there at all? If you want to email me a different plugin version and have me test it out, or you'd like to go to that test site you have access to, I'm all for it. Anything to help everyone out with this.
Have a great day!