bug#43587: 27.1; Org is breaking links

[Christoph Arenz]

    Org-mode is sometimes breaking links while adjusting indentation in
    org-fixup-indentation.
    This has been observed on emacs version 27.1, with org-mode versions
    9.3 (built-in) and 9.4 (melpa-stable).
    It also occurs with the current emacs development version.
    
    Here is how to recreate. I hope my mailer does not screw up the
    lines below...
    Enter the following text in an org buffer and proceed as described:
    
    * Org is breaking
      links!
        Create a heading with `*' and random heading text.
        Create a text section below the heading.
        In the text section create a separate line starting with a link,
      like so:
        [[simple-link]]
        [[http://a.b.com/demo.html][link
      text]]
        Switch on whitespace-mode to see what is going on.
        Indent the heading deeper (i.e. demote) with several
      `M-<right>' until the text starts with a TAB instead of
      SPCs.
        Then outdent the heading back (i.e. promote) with
      `M-<left>'.
        See the links getting corrupted as the two leftmost brackets
      `[[' are removed, in case of links with a target part, this also
      gets removed.
        Note that his behavior also affects org-refile: Links can get
      can get corrupted in this way while refiling.
        Note that links do not get broken as described when showing full
      links with org-toggle-link-display.
    
    Thanks for your help,
    Kind Regards,
    Christoph