Upon updating from 1.80.5 to 1.81.4 I have noticed the following warning being generated whenever a new scene is loaded while the game is running:

The scene named '' was not found in the Build settings.

Here's a screenshot of the warning revealing the callstack:

My game is configured to work with two players and the second player has a 'Scene name' defined in their 'Player start data' structure.

Here are some settings from the AC Game Editor > Settings pane:

Saving

• Reference scenes by: Number

Interface

• Movement method: Point And Click
• Input method: Mouse And Keyboard

Camera

• Camera perspective: 2D
• Moving and turning: Unity 2D

Scene loading

• [DISABLED] Always reload scene when loading a save file?
• [ENABLED] Black out when initialising?
• [DISABLED] Load scenes asynchronously?
• [DISABLED] Use loading screen?
• [ENABLED] Spawn PersistentEngine prefab from Resources?
• [ENABLED] Auto-call Resources.UnloadUnusedAssets?

No Addressables are involved.

I have noticed that if I replace the following line in PlayerStart.cs (line 157):

if (chooseSceneBy == ChooseSceneBy.Name)

with how it was back in 1.80.5:

if (chooseSceneBy == ChooseSceneBy.Name && !string.IsNullOrEmpty (previousSceneName))

then the warning is not generated.

My theory is that this warning is generated because the Default player has a previousSceneName equal to the empty string, as this is the default value of this property.

Let me know if you want me to provide more information regarding my setup.