Reproduction steps:
1. Open the attached “BugRepro” project
2. Open the “Assets/Scenes/MainScene” Scene
3. Enter Play Mode
4. In the Game View, wait for the player to fall off the map
5. In the pop-up, press the restart button on the left

Expected result: The Scene is reloaded and the game continues to run
Actual result: The Editor crashes

Reproducible with: 6000.0.55f1, 6000.2.0f1, 6000.3.0a4

Reproducible on: macOS Sequoia 15.5 (M1 Max), Windows 11
Not reproducible on: No other environments tested

Note: Steps 4 and 5 may need to be repeated if no crash occurs

First few lines of the stack trace:

{noformat}#0 0x000003c00a0514 in UnityEngine.Canvas:GetDefaultCanvasMaterial () [{0x1676bfd18} + 0x84] (0x3c00a0490 0x3c00a05d8) [0x144c02a80 - Unity Child Domain]
#1 0x000003c00a03c8 in UnityEngine.UI.Graphic:get_defaultGraphicMaterial () [{0x330dfc628} + 0x28] [./Library/PackageCache/com.unity.ugui@1a71b488df3e/Runtime/UGUI/UI/Core/Graphic.cs :: 97u] (0x3c00a03a0 0x3c00a041c) [0x144c02a80 - Unity Child Domain]
#2 0x000003c00a0340 in UnityEngine.UI.Graphic:get_defaultMaterial () [{0x3ad023c40} + 0x10] [./Library/PackageCache/com.unity.ugui@1a71b488df3e/Runtime/UGUI/UI/Core/Graphic.cs :: 477u] (0x3c00a0330 0x3c00a034c) [0x144c02a80 - Unity Child Domain]
#3 0x000003c009fe74 in UnityEngine.UI.Image:get_material () [{0x330f52e58} + 0x7c] [./Library/PackageCache/com.unity.ugui@1a71b488df3e/Runtime/UGUI/UI/Core/Image.cs :: 778u] (0x3c009fdf8 0x3c009fe84) [0x144c02a80 - Unity Child Domain]
#4 0x000003c009fd40 in BackGround:Start () [{0x330df9438} + 0x38] [/Users/vainius.sakalys/Documents/User cases/IN-111672_Climbing Cube/Assets/Scripts/BackGround.cs :: 21u] (0x3c009fd08 0x3c009fd88) [0x144c02a80 - Unity Child Domain]
#5 0x0000038f6d4970 in (wrapper runtime-invoke) object:runtime_invoke_void__this__ (object,intptr,intptr,intptr) [{0x395cd6db0} + 0x70] (0x38f6d4900 0x38f6d4a0c) [0x144c02a80 - Unity Child Domain]{noformat}