Bug EditorSceneManager.sceneOpened not called on Editor startup.

I have an editor script structured similar to this:

Code (CSharp):

1.  
2. [InitializeOnLoad]
3. class SomeClass {
4.  
5.     static SomeClass () {
6.         // ...
7.         UnityEditor.SceneManagement.EditorSceneManager.sceneOpened += (scene, _) => {
8.             // ...
9.         };
10.     }
11.  
12. }
13.  

The sceneOpened callback works when I open a scene from within a running editor; but it is not called on the initially loaded scene on editor startup (e.g. right after opening a project from the hub). However, I can confirm that the static initialization code does run on editor startup (so the callback is registered at some point early on), it's just for whatever reason, the callback isn't called.

How can I either a) get sceneOpened to also be called after the initial scene is loaded or b) hook into something else that's called after the initial scene is loaded (the GameObject tree must be fully loaded) on editor start?

2020.3.31f1, Windows 10

 

I was able to get it functioning as intended by adding an

EditorApplication.delayCall

callback, for now.

In the mean time, I'm going to assume I'm using

sceneOpened

correctly, and I filed a bug report.