I was producing 4k videos on the old version. I didn't face any problems adding Text or Transition. There was AVCHD among the video formats. But after updating to the new version, many video formats were removed. Every time I want to produce a 4k video, a flashing symbol appears when putting Text or Transition before and after the start. But when I change from 4k to 1080, this problem doesn't happen to me. This problem only occurs when producing 4k video. Even video formats, whether MKV or MP4, have nothing to do with it. Our problem is with the 4k system. Unfortunately, I still have this problem. I hope it is solved. Sometimes I wish the old version was better.