Inconsistent border

I'm putting together a short video of an logo I'm effecting to music. 

Its a square image and I'd like to keep black borders on the sides. 

When I cut and add effects to the image, the black border is there.  But when the image is un-effected, white borders show up. 

Anyone know what this is and how to fix?   The workaround is to add an effect and set it to zero, but I'm wondering how to correct the fundamental cause. 

Here's a video for reference, I'm sliding the mouse along the timeline, you can see the issue at 4 seconds and 8 seconds when I move into the un-effected sections:   dl.dropbox.com/s/immi814bm2mdelz/FinalCutBorderExample.mov?dl=0

Thank you!

It's a little hard to tell what is going on from your video. Have you played around with the crop and transform settings? What is the size of the original logo file with the white background? Or did you add the white BG?