The change in [1] seems to break the ability of rl_trim_arg_from_keyseq to properly remove arguments provided as esc-prefixed digits -- the _rl_del_executing_keyseq call removes the digit from the key sequence but leaves the esc (and the digit is never added back).
$ bind -x '"\eX": ":"'
$ ^[2^[X
bash: bash_execute_unix_command: cannot find keymap for command