Solid black image gets odd distortion when rendered as a movie

It's an odd problem I'm having that I can't figure out. I make a video that starts with a plain black screen, I use a black jpg. I fade in to the rest of the video and the first black image now has this weird, blotchy, greenish, fuzzy, hexagon kind of pattern all over it. I tried different black images, even made my own solid black in Photoshop. I tried it without the fade in. It always happens. It looks terrible on the big screen. I can't figure out what I'm doing wrong. Any suggestions would be appreciated.

Can you post a screenshot of what you’re seeing?

Try using an FCP generator to create the black screen.

Any reason you don't use a slug in the TL instead then cross dissolve / adjust opacity instead of this problematic JPG? The whole line of thinking behind using an image instead has me stumped.

Have used slugs, called gap clips in FCP, and dissolves without problems. Press Option W to insert it or select it off the Edit Menu.

I appreciate the tips. I really enjoy FCP but I'm mostly self taught. This is the first I'm hearing of gap clips. I will give that a shot.