Horizontal lines on screen when a mask is applied. It shows in different ways with different masks.

I can't figure out how to get rid of these horizonatl lines. They show up in different ways, depending on how a mask is used.

*I've included two screenshots–

–One is using a mask on the opacity of the Black Color Matt (and only effects the masked area)

–the other is when using the crop effect added to the Black Color Matt.

The lines seem to always apprear in some fasion when any mask is applied. This wasn't happening until I updated to the latest version of premiere beta.