iMovie PNG Problem I Can't Figure Out

Hi All, been lurking on this site and have always found great info on problems, but I just signed up because I've finally hit one I CANNOT solve, so I'm looking for some expertise. Hopefully someone out there will know what to do before I pull my hair out.

I've place a transparent PNG image in an iMovie clip. It works great, no problems. In the very next abutting clip, I placed another different PNG image. If I drag the cursor over the editing timeline, one PNG transitions perfectly into the other. They swap out right on cue. BUT, if I hit the play button to watch the video, the second PNG is simply the same image as the first only reformatted they way I wanted the second image to appear.

I really hope this makes sense. In the editing icon, my second image shows up. It's almost as if the program is taking the first image and automatically applying it to the second.

It's driving me nuts...there is a another PNG further in the video that's fine. I think it has something to do with them being right next to each other? I've deleted and re-pasted them, but I cannot figure it out.

Thanks so much

Joe