[BUG] Get "Args out of range" when trying to link heading with completion from inside a footnote

[lukeflo]

Hello everybody,

I'm writing a thesis and having trouble linking internal headings from 
within footnotes of my document. Its the first time I'm submitting to 
the mailing list, so if I oversaw some rules, just tell me so I can 
learn about it.

My problem is the following. When I create a footnote with C-c C-x f or 
org-footnote-new, and then try to link to an internal heading of my 
document typing [[*xyz]] and hitting M-tab for completion, I get nothing 
but the message in the minibuffer which says "args-out-of-range "" 1 
nil". If I manually type the name of the heading and export to PDF 
through LaTeX, the result is fine. But since some Headings are really 
long, auto-completion would be very helpful here. From everywhere else 
inside my document auto-completion for internal links works fine.

First I thought it might be due to my init settings and my completion 
package (corfu with cape and orderless). But the error remains even when 
I find a new file from the CLI with `emacs -q test.org` with the simple 
content of:

* A heading

Some great text. [fn:1]

* Footnotes

[fn:1] Link to [[*]]

The behaviour is the same as described above. When hitting M-tab after 
the asterisk, I still get "Args out of range: "", 1, nil" and nothing 
further happens.

Thus, it seems like a bug to me, since it is not working even with this 
very simple setup.

I'm looking forward for some hints, a solution or even a reproof if I 
propably made an error.

Best,
lukeflo