"git branch -f" corrupt other worktree

git version 2.21.0.windows.1

$ git worktree add ../wt master Preparing worktree (checking out 'master') HEAD is now at f534c32 4

$ git branch -D master error: Cannot delete branch 'master' checked out at 'C:/tmp/wt'

#but this is possible:

$ git branch -f master HEAD

#and the other worktree is now corrupted:

$ git status
On branch master
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)

        modified:   txt.txt
        deleted:    txtb.txt

greetings f.kulow