Comment 1 for bug 1970644

Work-around:

Add the following line in ~/.inputrc :

set enable-bracketed-paste 0

This turns off the bracketed-paste (mis-) feature everywhere (i.e. in any Xterm opened after updating ~/.inputrc).
To turn off bracketed paste only in the current Xterm, do this:

% bind 'set enable-bracketed-paste 0'

(Explanation: the bug reported here is actually due to the "bracketed paste" functionality, which has been creeping forward over the last 10 or 15 years, apparently. Much discussed on the duckduckgo, it has its advocates and detractors. I will happily remain neutral, as long as there remains a way (as shown above) to shut this ill-conceived time-wasting behavior down. (Ok, last one. I'm not bitter.))