Zoom into pictures on Premiere Pro (Ken Burns Effect) Not Working

Hi everyone,

I am trying to get a Ken Burns effect on my photo slideshow in Premiere Pro. I can't seem to figure it out. I have been following tutorials like this one to the T. All it does is create a rough transition to where my picture switches instantly on the new keyframe to the new scale percentage. I would like for it to be a gradual zoom. 

Has anyone had this problem before? Do you know how to fix it? I'd really like to use this effect.