Do a C-c C-c of the elisp code below ...
#+begin_src emacs-lisp :exports results :results none
(add-hook 'org-export-before-parsing-hook
(defun my-flush-headlines (backend)
(cl-case backend
(odt
(org-with-wide-buffer
;; Flush headlines
(flush-lines (rx (and bol (one-or-more "*") space (one-or-more any) eol))
(point-min) (point-max))))
(otherwise
))))
;; (remove-hook 'org-export-before-parsing-hook-hook
;; 'my-flush-headlines)
#+end_src
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