I have a weird flicker going on.

Question

I have a shape I created. It's an "S". The font style is impact. The letter is huge. I'm actually panning over it with the camera.
The camera start up very close on the top part of the "S" moves down and then pulls out to reveal the actual letter.
The animation plays fine. The "S" looks good.
I have some video footage I want the "S" to stencil.
I put the video footage and the "S" in the same space in the motion canvas. I group the two items. I have the S over the top of the video footage in my layers. I set the blend mode to Stencil luma. The letter is 100% white. Everything looks OK from a distance.
However, when I play the animation the "S" stencil flickers on and off at certain times for no reason I can find. There is no animation other than the camera. There are no keyframes, no behaviors. If I change the color blend mode back to normal the animation plays fine and my video footage simply looks like a big white S over the top of my video.
Any ideas. I would really like to use that **** S as a stencil.
-Fraky

Answer 1

OK. I've been playing around and I can definitely use some help.
Here was the goal.
Create a money symbol "$" have all sorts of different money symbols coming out of it as a particle animation. Sort of like a black hole/nebula/vortex of currency symbols.
I did a little test but it's a real pain working on it because of all the particles.
http://www.drewwfilms.com/QandA/blank.html
The flicker is there at the beginning as you are flying through all the particles. The particles literally disappear for 1 frame here and there. I am stumped.
Would love some help as it's very close to working.
-Fraky