Reproduction steps:
1. Create a new project
2. Install ProBuilder package
3. Create any ProBuilder GameObject in Hierarchy (e.g. GameObject > ProBuilder > Arch)
4. Select created GameObject and change Shape to Plane or Sprite in Pro Builder Shape (Script) Component
5. Change Shape to any other 3D shape and observe the Scene view

Actual result: GameObject does not change into 3D Shape
Expected result: GameObject changes into 3D Shape

Reproducible with: 6.0.7 (6000.3.0f1), 6.0.8 (6000.0.63f1, 6000.2.13f1, 6000.3.0f1, 6000.4.0a5, 6000.5.0a2)

Reproduced on: macOS Tahoe 26.1 (M4)

Note: GameObject changes to 3D shape if ProBuilder Plane GameObject was created initially