Projects broken, errors "Item could not be created". "Prototype cycle detected for type QQuickColorSpaceValueType in %2."

Steps to reproduce:

• Create empty project
• -> Project opens with error "Item could not be created" seen in Navigator. Please see attached picture
• There is also error "Prototype cycle detected for type QQuickColorSpaceValueType in %2." seen in issues view
• Tested with
  Product: Qt Design Studio 4.8 (4.8.0)
  Based on: Qt 6.9.1 (MSVC 2022, x86_64)
  Built on: Jun 29 2025 01:24:01
  From revision: 9cc212a3a5
• Last working snapshot without the issue was:
  Product: Qt Design Studio 4.8 (4.8.0)
  Based on: Qt 6.9.1 (MSVC 2022, x86_64)
  Built on: Jun 27 2025 01:29:40
  From revision: ea4fb5d156