Digital Workshop

I have written my publication and all works perfectly on preview mode. I am having some problems when publishing. Some videos are not included e.g. mp4 videos. Of those that are included I have some other problems. I have 16 different videos all made in the same way and identical sizes with identical settings in Opus - Chroma key, scale to fit, keep aspect. The problem is that at run time some resize themselves ... and some don't.