Are you using the latest release version? Yes
Can you reproduce it? Yes
Does it happen for a new document? No
If not do you have a document you can share that shows the problem? Yes
If you cannot provide a sample document then please give an accurate description of the problem for example it should include most of the following:
What is your operating system and version? macOS BigSur Version 11.2.3
What happened for you (and what you expected to happen)
Anker setzen, Hyperlinks setzen, Inhaltsverzeichnis setzen —> "Document must be closed"