Hello,

I've been experiencing the same issue on Emacs 28.1[1] since upgrading
HarfBuzz to 5.1.0 (with the previous version, 5.0.1, composed sequences
were not displayed properly, as reported in bug#56789[2]).

I couldn't reproduce exactly the same steps listed, because the command
C-x 8 e s is not available, but follows attached a screenshot to
illustrate the same problem faced by Protesilaos.

Thanks.

Footnotes:
[1] GNU Emacs 28.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.33,
     cairo version 1.17.6) of 2022-04-27

[2]  https://mail.gnu.org/archive/html/bug-gnu-emacs/2022-07/msg02241.html

-- 
Regards,
Fernando de Morais.