Cannot add existing tag to a tag hierarchy

With release 8.4, I cannot add an existing tag to a new tag hierarchy.

I have some existing tag hierarchies which remain unchanged, but if I create a new tag structure, I am not able to add any tags that are already in another tag structure.

For example, existing tags:

  • germany/munich/museum/cars
  • germany/sinnsheim/museum/cars

If I want to create a new tag structure like this:

  • germany/speyer/museum/cars

Then “museum” and “cars” have a tick in the checkbox, but when I press the “apply” button, “museum” and “cars” do not retain the tick in the checkbox anymore. Instead, they appear as new tags on the top level:

  • germany/munich/museum/cars
  • germany/sinnsheim/museum/cars
  • germany/speyer/
  • museum
  • cars

As a result, “speyer” is in the structure, but “museum” and “cars” are not, because they are already used in another structure.

With the previous version of Digikam, I did not have such problems. Is this a bug, or do I need to change something in the settings?