Rsync --dry-run issue

rsync-dry-run-issue.sh

mkdir ~/temp && cd ~/temp
mkdir dir1 dir2

cd ~/temp/dir1
echo Hello > a.txt
echo World > b.txt

cp -p ~/temp/dir1/b.txt ~/temp/dir2
# Now, dir2 contains "b.txt" file from dir1
# Hence, using rsync dry-run, it should only show "a.txt" as the file that is going to be transferred.
# NOTE: We used the -p flag to ensure that all metadata of "b.txt" is preserved.

rsync --dry-run -iav ~/temp/dir1 ~/temp/dir2 
# OUTPUT:
# sending incremental file list
# cd+++++++++ dir1/
# >f+++++++++ dir1/a.txt
# >f+++++++++ dir1/b.txt

# The output is showing both a.txt and b.txt, whereas we expected only a.txt as the file that differs.