Null Reference Exception in iOS build for some users. Not in Editor and cannot duplicate

My app is fairly straightforward. I embedded Unity as a framework into an iOS app. When a session is launched in the app, it switches to the unity window and from the "SceneLoader" scene it launches whichever scene it needs and then returns to the sceneloader scene and switches back to the native iOS window.

The issue I'm experiencing is that there's sometimes null reference exceptions in my build that shouldn't be there. I had experienced this once before in one of my scenes. There was a function that wasn't working in a script because of a null reference exception. The only way I could find to fix that was to add random Debug.Log lines in the function and build until it worked. That was ok because it wasn't a critical thing.

But now i'm getting null reference exceptions in a critical function that is causing the sessions in my app to not end. It only happens in one scene and only for some users but I can't figure out why there's this null reference exception and I'm unable to replicate the issue myself. In theory everybody's session goes the same way there's very little variation in the scene

Has anybody else experience anything similar? I'm looking into this potentially being an issue in references in the Unity Editor and so i'm trying to force refresh the whole project and hoping that will solve it, but I have no clue where to go from here.