Play mode forcing Scene save

Starting today I can no longer press play without Unity asking me to save my Scene first.

If I select “Don’t Save”, I get an error saying:

SBP ErrorUnsavedChanges
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

If i select “Cancel”, I get an error saying:

Unsaved scenes
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

If I do save, I can enter play mode.
There are obvious problems with this and I haven’t encountered this error before.
Thanks in advance!

Do you use Addressables?
If so, it may be resolved by setting “Play Mode Script” to “Fast Mode”.