Comment # 1 on bug 1026638 from Jiri Slaby

And it is caused by the new feature:
commit ec2da36ca48b40c0654b32a8d2c9f52e796daa5e
Author: Bram Moolenaar <Bram@vim.org>
Date:   Sat Jan 21 20:04:22 2017 +0100

    patch 8.0.0210: no support for bracketed paste

    Problem:    Vim does not support bracketed paste, as implemented by xterm
and
                other terminals.
    Solution:   Add t_BE, t_BD, t_PS and t_PE.


If I 'set t_BE=', it works again. I am not sure if this is a bug or feature to
set it for everybody.