During parallel downloading Xcode and installing homebrew, I stopped installing Command Line Tools for Xcode. Now I can see in Software Update two items related to that. With different versions. After clicking Update Now I can see a progress bar. But finally, the message doesn't go and it proposes me update that 2 items again.
I recommend to download the Command Line Tools 11.2 from More Downloads for Apple Developers. An Apple ID is required.
Install it manually and afterwards the pending (and obviously not installing) updates in Software Update will vanish.
As an alternative a direct d/l link: Command Line Tools 11.2