How to create a video for a map?

To troubleshoot the issue, please tell me: how do you close the editor with an open map? Do you simply click the close button, or do you go to File => Close? This is important.

StartDialogScene launches a dialog scene (which is what you were doing). StartCutScene launches a cutscene, but the technology for creating those has been lost.

I didn't mention this in the video, but I personally use the following function when creating: pressing the Spacebar opens the suggestion list window. By pressing Add, you can add a new suggestion, immediately specifying the "actor" (e.g., Svey 16:32), the text, and the duration (Pause after actors). You can specify a link to any unit in the animation here. HOWEVER: if you choose a link to a hero, the game may crash.

Just in case, I'll share my experience, which might help.
When creating a dialog scene, the very first thing I do is place a monster (an object in the Monsters tab) Random Any in some out-of-the-way place that definitely won't be in the frame. In each suggestion, I specify MonsterLink (a link to this monster), and not HeroLink. In the MonsterName field, I choose the appropriate file with the name of the speaking character, or a file with empty text. For each suggestion, the same MonsterLink is used. If you do this and don't make any major mistakes, the probability of a crash will be close to zero.