• Create new 3D project
• Add a material from content library, such as glass
• Click on the plus button of the same material, adding another instance to the project
• Check the contents of qmldir file for the material bundle in <project>/Generated/Bundles/Material/qmldir

--> qmldir file has two entries for GlassMaterial. It should only have the one entry.

Having extra entries for types in qmldir causes e.g. unimportFinished signal to never trigger for the type when it is removed from the project, because underlying code model still sees the type in qmldir file.