Comment 6 for bug 1925823

If I remain inside Ubuntu 21.04, but compile the previous version of bash, then the error disappears, ... this suggest that the erorr is not the consequence of the version of Ubuntu, but the "bash, version 5.1.4(1)-release" itself, or perhaps an Ubuntu specific configuration of the environment. In detail:

mkdir ~/bash

cd ~/bash

wget https://ftp.gnu.org/gnu/bash/bash-5.0.tar.gz

tar xvzf bash-5.0.tar.gz

cd bash-5.0

sudo apt-get install byacc

./configure

make

env -i PATH="$PWD:$PATH" ./bash --noprofile --norc

and here if I drop something containing a line feed character, the bash will correctly execute the currently edited commandline