Bug? Failed project template

In January i created some project templates and they work just fine.

Beta 2…9.9.10:

Now I tried to create a new project template. It was indeed created and I find it in the list of templates.
Then I wanted to create a new project with said template. A project was created , but it did not open in Scrivener.automatically as it normally does.
Then I looked for the project in the files and tried to open it form there. It pretended to be an old format, created the ususal backup, but still did not open. Looking into the files, both projects have the Scriv 3.0 structure, but neither opens.

For now, I can work around the issue ba renaming the “master project”. But there is certainly something worng.