Current questions and answers regarding the map editor.

Maybe try ONESHOT_STILL?

The thing is, I'm not doing this with animation, but with an effect. I create several effects: with closed gates, with broken gates, with opening gates, etc. Using a script, I launch the effect of closed gates. And then, when I need to open the gates, I stop the effect of closed gates and launch the effect of opening gates, but the trick is that after the gates open, they either disappear or open indefinitely, depending on the effect settings.
To create an animation, you need to find a gate object with animation, but I couldn't find one.