contain D not working in 4-4?

I cant seem to get this defense to work in the 4-4. It will work a little less then half the time. In the video from the 4-6, the tackle immediatly goes straight towards the contain. In the 4-4, the tackle will sit there and for a couple seconds, and then sometimes will go for the DE and sometimes for the contain. Im spreading my line, reblitzing DE, and putting LB on contain right behind DT. It might be my placement on the contain linebacker? IDK. any suggestions?