Steps to reproduce:
1. Create new Unity project using Universal 3D Template
2. Open Build Profiles window and switch to Web Platform
3. Below add Graphics Settings
4. Expand Shader Constant Defines foldout and press “+”
5. Above Graphics Settings, on the right side, press on kebab button and select “Reset”
6. In “Reset Settings” pop-up press “Reset”
7. In “Unapplied Changes” pop-up press “Apply”
8. Observe Console window

Actual results: “NullReferenceException” error is thrown in the Console after resetting settings

Expected results: No errors are thrown in the Console window

Reproducible with versions: 6000.6.0b3, 6000.7.0a2

Can’t test with versions: 6000.5.3f1 (No Shader Constant Defines settings available in Graphics Settings)

Tested on (OS): Windows 11, macOS Tahoe 26.5.1 (M1)

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.Shaders.ShaderBuildSettings.SplitAndValidateDefine (System.String define, System.String& identifier, System.String& value, System.String& msg) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Shaders/ShaderBuildSettings.cs:321)
UnityEditor.Shaders.ShaderBuildSettings.ValidateDefinesInternal (System.String[] defines, System.UInt32 numInternalDefines, System.String& msg) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Shaders/ShaderBuildSettings.cs:393)
UnityEditor.Shaders.ShaderBuildSettingsUI.ApplySettings () (at /Users/bokken/build/output/unity/unity/Editor/Mono/Shaders/ShaderBuildSettingsUI.cs:322)
UnityEditor.Shaders.ShaderBuildSettingsUI.HandleUnsavedChangesDialog (System.String buildProfileName) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Shaders/ShaderBuildSettingsUI.cs:307)
UnityEditor.Build.Profile.BuildProfileGraphicsSettingsEditor.OnDisable () (at /Users/bokken/build/output/unity/unity/Editor/Mono/BuildProfile/BuildProfileGraphicsSettingsEditor.cs:34)
UnityEditor.GenericMenu:CatchMenu(Object, String[], Int32) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:164)