Question Background flash after splash screen

I'm trying to do a fade in effect to start my game. However, I noticed that after building, there is a flash right after the splash screen finishes. For the effect I'm using a UI image that is stretched across the entire canvas. this flash doesn't occur when loading Edit: "other" scenes. I've tried changing build settings and timeline settings. I've also tried some code with functions like ForceCanvasUpdate(). I could have an intermediate scene that just has the background color of the splash screen, but that seems like a waste. I'd appreciate any insight on the matter.

I'll try and upload something if what I'm saying really doesn't make any sense.

 

That's what I do. All my games have a zeroscene file. It has some number of scripts, but usually just a script to load the next scene, plus zeroscene contains a black background frame (or whatever is appropriate).