This is expected behavior. After the initial asset library download, Blender may need to be restarted so the Asset Browser can properly index and display all newly downloaded assets. This is a known limitation of Blender's asset system rather than the add-on itself.

Most of the time, this happens because the asset's textures or materials were not originally structured in a way that the add-on expects. ShareTextures has been online since 2018, and over the years some assets were created using different naming conventions and workflows. Before releasing the add-on, we reviewed and updated as many assets as possible, but a few older assets may still cause issues. If you come across an asset that isn't working correctly, please let us know and we'll investigate and fix it as soon as possible.

The assets themselves are freely available on ShareTextures.com. The add-on is a premium workflow tool designed to make browsing, downloading, and importing assets inside Blender faster and more convenient. Your one-time purchase helps support the continued development of the add-on and allows ShareTextures, which has been serving the 3D community since 2018, to keep creating and releasing free assets for everyone.