Before the battle starts UFE attempts to preload some of the Game Objects. Select (or deselect) if you feel like this is causing issues in your game.
Hit Effects: Untoggle to stop the engine from pre-loading the Game Objects from Global Editor -> Hit Effects.
Player 1/2 Character & Moves: Untoggle to stop the engine from searching and pre-loading every Game Object from the character files that are about to fight and their respective moves.
Stage: Untoggle to stop the engine from pre-loading the selected stage prefab.
Warm All Shaders: Run Unity's own Preloader technique before the battle starts. (for more information click here)