How to reproduce:

1. Open attached “IN-142268_MeshRenderer_CustomEditorIssueInURP_bug” project
2. Open “SampleScene”
3. Select “MeshRenderer-Issue” GameObject
4. Inspect “Mesh Renderer” Component

Actual result: “Mesh Renderer” Component has default editor
Expected result: “Mesh Renderer” Component has custom editor

Reproducible with: 6000.3.0a5 (f9a1fab5607a), 6000.3.15f1, 6000.4.7f1, 6000.5.0b8, 6000.6.0a5
Not reproducible with: 6000.0.75f1, 6000.3.0a4

Reproducible on: Windows 10 (User), Windows 11

Workaround:

1. Open “MeshEditor2DURP.cs” script (Packages > Universal Render Pipeline > Editor > 2D > Overrides)
2. Change “[CustomEditor(typeof(MeshRenderer))]” with “[CustomEditor(typeof(MeshRenderer), isFallback = true)]”