I'm surprised by this behaviour. 

#+begin_src sh :results replace output
ls
#+end_src

#+RESULTS:
: file1.txt
: file2.txt

Adding :dir parameter changes output RESULTS. It's now wrapped in #+begin_example #+end_example block.

#+begin_src sh :dir ~/ :results replace output
ls
#+end_src

#+RESULTS:
#+begin_example
file1.txt
file2.txt
#+end_example

Is it a bug?

Org mode version 9.6.7 (9.6.7-gc74c4a @ /home/slk/.emacs.d/straight/build/org/)

GNU Emacs 29.1.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0) of 2023-07-30

Regards,

Sławomir Grochowski