I created a video in Adobe Express (the web version on my Mac laptop, using Chrome) and then today I realized my downloaded file was missing the first third of the video. I went into AE to check and found that the video was missing that chunk there as well. I was able to go into version history, retrieve an earlier un-chopped version and then save the full thing again, but it was very unnerving and I see it's happened to other people too.