The following code will let "backspace" correct an unwanted jump to comment-column, deleting all previously inserted whitespaces.

example of phases before and after typing bla();#<backspace> (cursor position marked by «)

...
   bla();«
   bla();                            # «
   bla();«
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elisp:

 (defun my-cperl-electric-backspace (arg)
   "(Wrapper for my electric commands)
Remove inserted whitespaces or call `cperl-electric-backspace'"
  (interactive "p")
  (if (not (eq last-command  'my-indent-for-comment ))
      (cperl-electric-backspace arg)
    (setq p (point))
    (skip-chars-backward "# \t")
    (delete-region (point) p)
    )
)
  
(add-hook
 'cperl-mode-hook
 (lambda ()
   (local-set-key (kbd "C-#") 'comment-dwim)
   (local-set-key (kbd "#") 'my-indent-for-comment)
   (local-set-key (kbd "DEL") 'my-cperl-electric-backspace)
   (set-variable 'cperl-comment-column 60 )
   ))
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