Hello !
Haha, that’s a weird problem but it can be a lot of things.
The first thing you can do is to check its properties.
In the Rendering section it should have checked “Visible” and “Visibility Gameplay”
Also look that “Actor Hidden in Game” is unchecked
Also, in the Sequencer. Isn’t animated any weird thing?
Sometimes unintentionally Unreal make a key in location, scale, maybe Hidden in Game.
Let me know if any of this helps you!